[Harp-L] Minimum amp requirement for using an RP?

[martin oldsberg <martinoldsberg@xxxxxxxxx>]

Lately I´ve been playing a few coffee-shop gigs just using my Roland Micro Cube (5W). There´s no PA.
  It works OK for such small rooms, a bit low perhaps -- but I´m slightly annoyed that I can´t add my RP 150 (with Richard H´s settings) to it in order to get a somewhat broader palette of sounds. (It´s feedback from the very start almost; couldn´t even reach convincing volume levels if the gigs were in my living room.)

Question: How strong an amplifier do I need to fill say, an 80 square meter room with, say 50 people in it? And I mean when also using the RP?
  Impossible to answer precisely? 

  Yeah, I know -- but roughly: 15 W? 30 W? (I understand from Richard´s instructions that a keyboard amp can be a way to go, but how powerful?)

Cheers,
Martin