Banquo363, a 20' X 35' requires something serious to pressurize the room the way some require. You did use the word, moderate, so I would say it comes down to how much of a headbanger you are.
I agree with Paul's comments regarding the RM10, and he and Rnadell on Music Reference amps in general. If you can buy an RM10 for $1550, in my opinion, that has to be one of THE flat out biggest bargains in high-end audio.
In my experience, there's far more to how a loudspeaker and amp couple than just watts. People will throw a lot of other numbers and specifications out there, but I'd say oftentimes need to give the match a try, as some surprising things can happen. I would have honestly scoffed at someone suggesting I listen to a physically diminutive 35 wpc EL84 based tube amplifier with the Vandersteen 2s before hearing what I previously described. Shows you how much I know...