I am currently biamping Revel Salons with 4 436 monoblocks in a vertically biamped setup. At this time I don't have matching interconnects going from the preamp to the four amps. One can easily tell the difference between the sound quality of the bass and treble. The system sounds better in many ways but is not as coherent. As a result of this experience I would not use two different types of amps. It sounds good in theory and on paper but if the two different interconnects cause concerns (I'm awaiting a matching Synergistic interconnect!) then with speakers as reportedly accurate as your 801s I don't think you'd like the results either. (I've not heard teh 801s.) An electronic crossover and horizontally biamping would be better, but is more expensive (finding a good crossover is tough) and I still don't think you'd have a seamless sound. In my experience you have to match the amps, powercords, interconnects, and isolation exactly the same for the best sound. But if you can do it, biamping is the way to go. Last night my system was amazing! I've never heard dynamics, resolution, details, and low end like this ever from my system.
Good listening,
Steven
Good listening,
Steven