7.1 Sound and Bipole/Dipole v. Direct Radiating

currently have a 5.1 set-up with Wilson speakers all around (ex sub woofer). I have Watt Puppy L/Rs, and a Watch center and surrounds.

My question is about the surrounds. The Watch surrounds are not bipoles/dipoles. I think this is o.k. for rears in a 5.1 set-up. However, I'm moving to a new house and plan to set up 7.1 sound. My sense is that in a 7.1 set-up, I want true bipole/dipoles for the sides throwing sound away from the listener (with the rears o.k. as direct radiating speakers still pointed at the listener). If so, I'm not sure what to do as I don't want to go to another brand for just the sides, and don't think Wilson makes matched bipole or dipole surrounds/sides.

Any advice would be appreciated. I know there's a significant chance I'm out to lunch in my understanding of this issue.

Completely understand you're rather pertinent and informed question! YOu bring up a valid issue and situation with which to consider. I've sold Wilson's in the past, and know the speakers. Yes, you would and should stay with ALL WILSONS in your case if you ask me! Anything else will be likely a compromise for the worse.
One thing I would have to see is your room and potential future set up! If the room is "workable" you could do more of the wilson surrounds for sides(or rears) with your 7.1 system in the new place!..but it depends. Really, ultimately, considering also the proper soundstage, you want your speakers (all of them, including sub) placed where they will couple with the room and your listening seats yielding EVEN AND FLAT FREQUENCY RESPONSE!, as well of couse a proper immage and soundstage. MOst never achieve this with any set up!!!!(espeically the more speakers you have, i.e, 7.1!). No matter what speakers you are using, or where they're placed in the room, if they don't SOUND RIGHT, you might as well not use speakers there at all!...and just try to concentrate on, say, maybe 2 speakers, and maybe a center!!! Adding quantity, and not quality is not the way to go. It's better with 2 properly set up speakers and a sub, than to have 7.1 speakrs of "NOT SO WELL SET UP CHANNELS!" Still, a PROPERLY SET UP 7.1 system (mostly never pulled off right by novices) is STELLAR!..even mind blowing!
So, what I'm saying is there needs to be some quality of effort involved with "PLOTTING POTENTIAL SPEAKERS LOCATIONS FIRST(as well as potential seating AND ACOUSTICAL CONSIDERATIONS ALSO!!!!) before you NEED TO DECIDE which speakers you can or can't use!
In your new place, given all the varriables, someone with my experience might just look at your room and set up and recommend more dirrect radiators like you have now! It's entirely possible, and maybe practical. Then again, in anothe room, perhaps dipoles would be more ideal. It ends up being compromise sometimes. Still, there's issues to deal with that will MAXIMIZE the results...you just have to know what those are.
Acoustics of the room and set up have a lot to do with which of these speaker designs do best for their applications.
So, yes I am personally am an advocate of "dipoles and bi-poles" for surrounds. But, yes, You can however, depending on the "execution" get fantastic results over a wide area(depending on needs) with "dirrect radiators", like the Wilson rears!
At this point, I would want to see what's going on with your new acoustical environment and plans to recommend. If the situation ends up not being ideal for a "di-pole consideration" (which is probably the case if you stick with your Wilsons as it stands), considerations might be adding another pair of rears, and placing them higher up on the sides, even the ceiling!..or maybe firing across the room or away from the listeners head at the side locations! There's lots of options. Then again, there's still challenge,(i.e, tonal balance, room coverage, soundstage ultimatly, acoustics, etc..like I said). The dirrect radiators, like the Wilson's are balance for "dirrect aimed sound mostly...not dipole reflective sound, yes. Still, it's workable if you know what you're doing. I might opt, depending, to fire more speakers up high and too the sides at an angle across the room, and maybe use one rear speaker mounted up high in the back or on the ceiling in the back as well!...would have to be looked at though.
One other thing, is that someone who's knowledgeable in doing this might walk you though just using your existing rears as side speakers in your new place, until you can determine if and where they "MIGHT" work best in that application. Once you eliminate all the varriables, you might be able to see if they will be workable as "sides" in your room. And, if so, you can then get another speaker or two for the rear(again, depending) and place that one accordingly!
Trying to "do it all at once" often isn't the way to approach it anyway. Doing one speaker at a time(or pairs if you must) is the way to go! REally, one at a time is the way. If you can get great results with your rears as sides, you know what you can do. I would then try to live with that set up overall, and fill in the other speakers accordingly.
One thing you might do is set up the rears/sides as "mains",and play a lot of 2 channel through JUST THOSE SIDES as if they were a couple of "mains"! If you can get excellent stereo sound from them set up from your seat to the sides, then you know you have them set up weill for sound ovearall! And, if they sound balance(measured as well) and acoustically sound, your in the ball park. So, I would recommend focussing on trying to get just those set up from (all listening possitions), to see if they're workable, yes.
Ultimately however, what I find is that doing it right might be left to the professional and more experienced (someone like myself), and it will pay you HUGE DIVIDENDS in the end! Especiallly with your level of gear, the REAL RESULTS are going to be how well things are set up, the acoustical consideration, the proper crossover points and phase between ALL SPEAKERS AND SUB IN RELATION TO EACH OTHER, from ALL LISTENING POSSITIONS IF POSSIBLE(you'd be shocked at how rarely, if ever this even occures how the recording engineers designed it to sound in most homes!), and get proper tonality, immaging, and soundstage from all listening possitions...not to forget the tweeking and calibration. Add up all these results done PROPERLY and COMPETENTLY, and you'll have something special, even WORLD CLASS!!!
So, to sum-up, you might not need to consider a set up with dipoles. You CAN GET fantastic results with different designs in the rears if you're careful. A lot of knowledge here goes a LONG WAY!
Maybe we can talk about your set up sometime?.
Good luck...hope this helps.
One more thing....I just wanted to add that "di-poles" are indeed more forgiving of side posssition, and often more effective on their own in that application. Something "side-mounted di-poles" do so well is NOT DRAW ATTENTION TO THEMSELVES, and they are more forgiving of listening possitions that are nearer to their location vs. "dirrect firing" designs! You can sit right next to dipoles to the side, and they still won't pull you out of the movie with distracting/dominating sound! This is a definite plus! Still you have to balance everything out in the end. And, in your case, since Wilson doensn't make nor advocate the use of Dipoles, you might be better off trying to make their rears work as sides. Other than that, you could consider other surround speakers. But if this is not a consideration, I'd get the Wilson rears up away from the listeners so they are less localizeable and dominant.
I would like to see you (Casness) get great results with your system, since you've obviously investen in the gear so ambitiously. You might want to weigh all this out some more