How to choose speakers that won't overpower your room?

I am considering buying new floor standing speakers to replace my kef reference ones stand mounts and I'm wondering how to avoid buying something that overpowers my room. My room is fairly small 12 1/2 by 11, And I listened at fairly low volumes mostly jazz and some rock.

I will use Sonus Faber as an example, I'm thinking the Olympica Nova 2 or Nova 3 might be a good fit and I also look at the Serafino, and think that would be very nice as well, but I have no idea if these would be too much for my room. They all look good on paper. And yes, I realize that I have to go listen to these speakers I've never even heard them before, but still auditioning them at a dealer or somewhere else is not the same as putting them in your small room.  Are there any technical details or cue that would tell me whether or not the speaker might be too much for my room?

Bonus question I am going to AXPONA next week is there anything that I absolutely should hear when I am there?