Sonus faber center speaker as front?

In addition to the comments already made, my major concern would be bass delivery. Most center channel speakers don’t deliver lower than 45 HZ, where most floor standing speakers will drop into the low 30’s even the 20’s. Unless you plan to supplement with a sub woofer. And if you were to set them up vertically, how would you accomplish that 

The dealer obviously wants to sell them, see if you will let you take the money home to see how they interact with your room

I think the dealer has resolved your dilemma. Good hunting, it took me 2 years

to decide.

Bargains are tough to turn away from, but sometimes you look back and realize

you made the right decision.