@maxwave Sorry if my thoughts wasted your time.
@creditingkarma You are right. The YB MK2's don't require 400w mono blocks. I bought the amps as part of a plan to do a significant remodel that would have given me a much larger listening room and an opportunity to try bigger speakers. For reasons not related to audio those plans changed.
My current listening room is small. It's kind of an L shape, 12 x 16, widening to 15 in the rear. The shape is the result of a bathroom and two doors. The room is below grade and very solid so the sound right now is great. It's a very quiet room, <30Db background. The Estelon's image really well though they are short on deep bass.
So yes, I originally planned to move to bigger speakers. Plans changed and everything sounds so good right now I'm reluctant to change. I finally have a turntable with two tonearms and I'm enjoying experiencing different cartridges.