Can some of you experienced builders give a brand new builder some tips on back riveting? I have a new 3X rivet gun and a back rivet set and plate with no instructions. What air pressure is recommended? Should I start by pushing down on the collar of the set to fully compress the spring in the tool until the die is in contact with the rivet head before squeezing the trigger or should there be a gap between the tool die and the rivet before firing the gun? Should I try to tap it lightly many times to set the rivet or should I hit it hard just a few times?