Is there a max number of weights that should be put on the wheel? I just got a brand new set of wheels/tires and one wheel has 12 weights while one only has 3. I've never seen a wheel with that many before.
theres no max, but pending the weight of the wheels and quality of the wheels and tires, they may not balance out nicely as each other. One thing that can be done is the shop can '180' the tire. Spin the tire on the wheel 180 degrees to move the heavy spot to even out the weight distribution.