Brad, I personally use the spring tip style not the pilot style. I use a center punch and set the spring tension pretty high. This will keep the tip from wandering out of the punched hole but causes a little quicker arm/hand fatigue. I only "cut" through one side for things like floor pans, trunk pans, wheel wells, skins etc. as you don't want to damage the structural base metal that you need to attach to. on other parts i might go through both if you can access the base material from behind to weld through as mentioned above, but typically i just go through one. Just remember, if you can't fill the hole, it will cause a weak spot and a place for dirt/moisture to gather.
Todd
