I did three roasters at once using three slightly different methods. One was a beer can chicken with a stand. Another was just marinated in Italian dressing overnight and put flat on the smoker. The beer can chicken and the third chicken I put a rub on and left overnight. Ovbviously, the beer can chicken just got liquid in the can (1/2 beer, 1/2 Italian dressing) and that was it. The third chicken got basted with a sauce made mostly of margarine (not butter), water, worchestshire, and other spices. The sauce was basted on at beginning of the smoke and again at half way point. The recipe called for the sauce to be added again at the end, but it didnt need it. I did turn my chicken half way through. Started breast side down then turned. Depending on what kind of smoker you have, you may prefer beer can method just to get more chickens on the smoker.
By far my best chicken was the once with basting sauce. Hands down it was the winner. All tasted good, but the third one was out of this world great! You mentioned getting more chicken breasts, you might just get a couple more whole chickens. They are pretty cheap and any leftovers can be used in so many ways.
Good luck. I am sure what ever you make will be very tasty.