Bi Amping

Hats a good point, thank you

Bi amp with identical amps. 2 stereo amps, or 4 identical monos. If you do otherwise you will introduce phase, frequency response variations, gain variations under different input voltages, and will never get the coherence you might otherwise achieve.
I toyed with idea for a good while, talked to many people more knowledgable than I. If you're like me with a limited ability to modify and electronically alter equipment you won't outsmart electricity. Here's what I found to be successful
Focus on phase coherence, time aligned speakers with minimal crossovers and balanced, differential equipment all the way through to balanced power in the electricity. That's where the magic is allowed to enter.

Kellymack----I'm biamping a DIY set of speakers that are similar to Legacy Focus using a big 805/300B SET tube amp (45w) to drive the midbass drivers, midranges, and tweeters while I've used some big bruiser integrateds to drive the 2 12" woofers per side with the best results from a Consonance Calaf.  I'm moved to pro audio amps with built in volume controls to  pull funds out of my main system and, for these speakers, the results have been excellent.  My sources have built in volume controls so that controls both amps and I can fine tune the bass with the volume controls on the pro amps. 

But.....I tried the same on a pair of BG Corp 520DX loudspeakers, using a different tube amp on the ribbons and a Hafler P3000 pro amp on the bass drivers and it never sounded coherent.  So, try it and see.  If you do biamp, why would you go with a 30w tube amp for the bass drivers?  I'd think almost any decent solid state amp would do a better job.  YMMV and best of luck with it.