What are your typical listening levels (qualified guesstimates are fine)?

Hmm depends on the music. Most rock the average unweighted is in the low 90's weighted in the 80's


How does one best mechanically decouple the speakers from the floor?

I built stands on castors so the only thing touching is the wheels tangent point. Can't image much energy coupled through there. You have a pair of short strong foot stools???

(So what do I think? In short: This really should be a "non-brainer"...but (always a but) I have concerns, the nature of which you can tell from my questions... I already get the evil eye from a neighbour due to practicing bass (guitar) and electronic drumset using headphones. )

Oh boy! Glad I don't have to deal with that. You friendly at all?? Could invite to your next party when you celebrate your new additions???

Rob