Picking an Open Baffle speaker for 2w SET amp - plus bonus question !?!


https://imgur.com/a/PCQXpKa

I recently purchased a Decware Zen Triode 2.3w amp and want to experience what an OB speaker sounds like - with a budget of $1000. I do own 2 REL T5 subs that could be put to use if needed, and from looking around, especially on the Decware site, one obvious choice would be a Caintuck OB with either a Betsy or Lii Fast-8” full range driver. Others on the user forum site rave about the Lii 15” driver (in the same baffle) for offering a much fuller sound.
Where I get confused is primarily if I should go with one of the 8” driver options or with the 15” big boy. I am guessing the answer will have a lot to do with my particular room situation, which is very restrictive and from what I have read not ideal for OB speakers.

I am hoping someone with more experience could take a look at my odd room (floor plan & a couple pics attached) and make an educated guess what would perform better in my set-up (15” or 8” plus sub).

There are two rooms I’d like to try this out in:
One is my office, a “tidy” 12x12’ box.
The other is the more complicated space, a living room with an interesting layout.
https://imgur.com/a/PCQXpKa
The bonus question:
Is it possible with the addition of another device (and what would that be??) to control / set a crossover frequency for the Decware amp, when connecting a sub via the speakers tabs from the amp?

nkphoto
I have the Caintuck Lii-15s and dual Rel T-zero subs. They get plenty loud in my 12x18x8 room with my 1.5 watt type 45 tube amp. They don’t have enough bass without the subs but will have more than the Betsys. I would expect the 8” Betsy’s to be fine with your subs. Be aware that with the 15”, you now must purchase your own drivers. These speakers benefit tremendously from Dirac room correction. I use the miniDSP SHD studio and a separate DAC for my subs (good DACs are <$100 these days). I also use the SHD to crossover the subs at 80hz. In your small square room, you will benefit from acoustical treatments on the side and back walls. Otherwise, the overall system may sound boomy due to room mode resonances. You can use REW to optimize the room for your subs and plug in the parametric constants into miniDSP’s PEQ equalizer. MiniDSP has a nice article on sub integration with REW.
@larryi  
that is great info on the different drivers, thank you!I am indeed considering diy and using the Lii Audio Fast-8 fullrange drivers - but will take a look at Tangband

@tweak1 great tip, thank you!
@ozzy62 Yes, very much aware that I need super sensitive speakers and that I have very limited options.

@ricwa Fantastic info, exactly what I was hoping for. Never understood what those miniDSP products were for, and have also never heard of REW.  Thank you for being so detailed, I have some homework to do now.
Re: crossover. Given you are working with the Lii 15" driver, is it safe to assume that the crossover will need to be quite a bit higher when using an 8" Betsy or Lii Fast-8 (or Tangband..), or is that not necessarily the case?

@bache 
Yeah, my money printing machine recently died, so $1k is all that's left besides 1000 cans of Ravioli and home schooling my kids. No idea why only 2-3 watt from the Zen Triode, maybe broken too?
Dual subwoofers may allow you to crossover at a higher frequency but no, it’s not necessarily the case that a smaller driver necessitates a higher crossover frequency. 80hz is a good starting point. Finding the optimal crossover point is another use case for the REW software!  See roomeqwizard dot com.
@ricwa awesome, thank you. Just reading about all the different miniDSP products. If all I want to do is follow your advice, adding room correction (Dirac) and setting crossover for sub integration, could I do that with the DDRC-24, "a USB DAC+DSP Digital Room Correction processor powered by Dirac Live"?  What does your miniDSP SHD studio offer in addition that I should consider?
It looks like the DDRC-24 has all the same functionality as the SHD minus the streamer. You might post the question on the miniDSP forum to be sure. BTW, if you go with a Tang-Band or other driver, you need a driver optimized for open-baffle usage. Not sure you want to open that can of worms but it starts with a higher than normal Qts parameter. There’s an OB forum on diyaudio that can educate you to that end. I know the TB W8-1808 8” full range is well regarded but it’s expensive relative to DIY prices.