MC60's for Magnepan 20.1 top end?

I have a friend who has been thinking of getting into some Magnepans. He has a large room, I'm going to guess about 36'x22'. He has Older Mcintosh gear, 2. 2100's running in mono and MC60's for the top end. Seeing as the 2100's were bench @ about 150 WPC I would think they should be darn close to 300 WPC in mono mode and we belive that should be good enough. My question is will the MC60's be up to the task of running the ribbon tweeters? Also when by amped is the tweeter solely the top portion of the speaker? We are well aware that more power is desireable but can't help but wonder if this combination will work. He does listen to lots of classic rock and this could be a problem at higher volumes.
Bi amped Maggies are woofer for one amp, mids and tweet for other amp. That is how they are wired, and power wise makes most sense.
I also listen to classic rock on 20.1's
I believe this speaker has ruined every box speaker for me, unless I am lusting for dynamic punch in the chest, which truthfully I can do with Yamaha pro gear from Guitar Center.
I have finally gotten pleasure from bands like Zeppelin, which I honor from a historical standpoint, but normally the music is way too smeared and noisy.. The 20.1's layer that out into incredible separate image layers that simply can not be beat (to my ears).
The Maggie tweeters are vertical the whole length of the woofer, so no top imaging is present.. The image is basically identical from standing or sitting.
I use VTL MB300 KT88 monos, which are 300 WPC and I am in pure heaven... It is truly therapeutic..

I think your combo will work well... 60 WPC for the tweeter should be fine..

Cheers !