Ideas for Biamp with mc611 and mc275?

It can be done but you need to preamps/volume controls.

the first preamp needs two outputs. One would go to the less powerful amp and then one would go to the second preamp/volume control then out to the more powerful amp. This way you could adjust the balance with the second preamp then use the first one as a master. 
 

For what it is worth my local shop was playing around and use a MC275 and MC7200 to byamp a pair or 805D3s. I did not listen in extreme detail but it sounded nice on the surface. 

The Men 220 has crossover controls that you will need to send the signals from the 2 different amps so that they do not try and play the same signals to the speakers. 

Maybe trying a tube pre with the Mc611's?

I’ve done this for years and it sounds excellent. are use the Macintosh C50 pre.  Speakers are Tekton Moab with the bi-amp crossover. Everything sounded balanced and perfect, except that I had cleaner base, more base, actually and warmer mids and Highs.  I have to believe that the mackintosh MC 451 amp is maybe a little bit better because it was designed exclusively for the task at hand.  I believe it’s called horizontal bi-amping.

@raysmtb1 

What crossover device do you use for bi-amp?

I saw your system, is mc275 used for the higher ends?