Personally, I think predetermining which club you are going to use will limit the variety of shots you can play. I would say that you should assess what the lie is, how much green you have to work with, is it downhill/uphill, carry distance, etc., THEN decide on which club you want to hit. However to answer your question, getting spin on the ball requires descending blow through the impact zone. Think of it as if you have a golf ball just sitting on your desk/table,etc. Put your finger on the top of the ball and press down hard as you move your finger back towards yourself. The ball will shoot out and have backspin on it. The harder you push down on the ball the more backspin it will generate. The same idea applies to the golf swing.