Strange Lacee, your "small" room is not much smaller than my 15 X 25 X 9 room. I can't imagine that 2 watts would drive the GV's.
I would not say that the GV's are a very efficient, in fact my old speakers were more efficient, and I tried a 12 wpc SEP amp with and a 35 wpc EL34 amp that couldn't light the room up the way my 85 wpc VAC amp does. Since the GV's are slightly less efficient than my old speakers were, I can't imagine driving them with less power. More power? Maybe one day. To each their own.
Interesting that you compare the GV's to electrostatics. The gent I bought them from said that the GV's were to only box speaker that he has ever heard that could compare to stats.
Cheers,
John