Drive the bass panels with the bigger amp, they require more wattage than the mids/tweets.
I once thought as Mr R does, then it occured to me that the vast percentage of the music actually is in the mid-range(250hz and up)and therefore sucks up the most power. As both of your amps are SS: I'd recommend the larger(IF it is the cleaner, more lucid of the two) on the top. The extra dynamic range will be more beneficial(sound wise) there. Of course: I'd also recommend trying it both ways to satisfy any doubts.
I agree with Rodman99999 - Use the larger amp for the mid and tweeter ranges. I recently read an article (wish I could remember where) that said that contrary to popular notion, the larger amp should be used to drive the upper ranges. I recently got a pair of 20.1s and would love to see some follow-up on this from you after you get hooked up. Trying the amps both ways is a good idea anyway.
Try it one way, then switch, then keep switching until you can decide which sounds better to you.
I'm curious if there is much difference, i would expect either ice amp has the power and juice to handle either task very well.
My guess is that there is a significant difference, it will work better with the bigger amp on the low end.
But it really sounds like a win/win scenario to me regardless.
I would be surprised if you got clipping from those kind of powerful amps with the maggie. Unless you are really punishing the maggies with very high SPLs and popping fuses all the time. I would have thought the bass panel would start rattling as it hits the magnets long before those amps give up.
My only reasoning for putting the 1000w on the highs and mids would be because the 1000w ICE board is a better sounding amp. Otherwise I would use more power on the bass.
Having said that, just plug them in a see which way you feel sounds better!
Agree with Chadaffect.
HAving owned Maggies and researched the Ice amp units, I seriously doubt clipping will be an issue. I believe they double in power pretty well from 8 to 4 to 2 ohms, so load should not be a problem.
If one sounds inherently cleaner or better for some reason listening at typical SPLs , I'd put that to the high end first most likely regardless of power.
I'm not certain more power makes as big a difference in the low end with maggies as with say equivalent dynamic box designs, so power to the bass may not be as much a factor in the Maggie case.
I wish I knew about the latest ICE power amps before I sold my Maggies a year or so back because my impression researching them is that their cost effectiveness and ability to deliver current to handle difficult loads may have been just what the doctor ordered.
I have to say that all planar users should spend some time with ICE power amps regardless of budget.
They are a marriage made in heaven for full range planar speakers. Some ICE amps are better than others or suited to a certain balance of sound, but their ability to keep the panel under control and give you huge amounts of clean, undistorted power make them almost a miracle when you look back at what was available just some years ago.
I bet the MG20 sounds great with them as would all maggies I am sure. I would love to hear a Martin Logan CLS or CLX with them.
Regarding which size of amp to use on which part of the frequency range, I think Mapman is right. Use the cleanest sounding on the highs/mids and the other on the bass.
Call me an audiophile, but my worry would be towards the xover itself and the differing amps on such a capable and resolved speaker.
If you have the resolution you may find artifacts in the presentation especially with soundstage. Real recordings of ambience such as in orchestral recordings may loose that top to bottom unity. Something these speakers excel at. It would be dependent on where the bass cut off is and obviously if its very low you may get away with it.