Adding players on arranger gigs is a joy. I have an extensive list of players, and use them whenever the budget allows. It's so much fun that I sometimes take a little cut in my leader's share to make it happen. I frequently use a flugal horn player, guitar player, sax player; sometimes a percussionist, which "sweetens" the rythem section nicely.
My favotite combo is guitar and sax/flute from an old group (been playing for over 30 years together off and on) and a drummer on percussion.
Until an accident put my left hand on 50% effectiveness, sometimes, I'd use these guys with a B-3 for large country club dances.
Playing with other players is, in large part, what music is all about-for me, at least!
Russ