I just wanted to second Stevtt's preference for triode mode on the amplifier regardless of whether the active gain is used.
Also, I have the M180 monoblocks and have been using Gold Lion KT88s in them since I got them three or so years ago. I recently tried a set of KT120s in them and didn't like them nearly as much. The GL KT88s were more holographic, textured, clearer. If you have the opportunity to upgrade the amp to the GL KT88s it is worth it in my opinion. If you are getting the amps from Rogue, just ask Mark O'Brien about it. There will be an up charge of $100 to $200 I guess, but I would recommend it. And if you are not getting the amp from Rogue and it doesn't come with the GL KT88s, you can eventually upgrade from Rogue, which is my preferred route since Mark rejects tubes that don't pass Rogue's quality requirements.