What jammers like...

Just provide the instruments in a public place and musicians will play regardless of ambience. I have the instruments but I do not have a public place or even if there is going to be one, at my friend's forthcoming shop opening, when I think of the moving of instruments and my poor back, I won't be able to enjoy the play. See the difference? Most musicians (whatever their level of play) are willing to play for free if everything is conveniently provided.