Quicksilver Mid Mono - power matching


Looking at a pair of QS Mid Mono tube amps. It looks like they put out 40-50 watts depending on the tubes. I'm trying to figure out how much speaker I can power with these. I've heard sensitivity is an important concern and that I should be looking at speakers with 91db or more? Is that good advice? Do folks have thoughts, guidance on this?
spotconlon
I love QS gear.....  Mikes new headphone amp is incredible....  all Quicksilver components are a huge bang for the buck
spotconlon OP
Looking at a pair of QS Mid Mono tube amps


These are what Sam Tellig (Sterophile) has and loves (his favorite amp) and because they only need 1.2v input for full power output, they only needed my Lightspeed passive pre which he uses with them, as nearly all sources will have more than 1.2v output, cd is min 2v and even phono stages are over 1v

Cheers George