Yes i am here! lol!
ok a few things that will help. 1 st you can really adjust the tightness to an extent. When i say lean against a wall and do a pushup , and while arms are back as far as they can go, pull the straps tight. You do the opposite. Make a "mostmusclure" pose, you know like the incrediable hulk, and while your arms are forward lightly close the velcro. As you get stronger(your tri's) tighten the back up. This will allow less weight to touch.
2nd when the shirt is on have your partner pull the front down and wrap your belt around it. Not tight just snug. Once the belt is on , and the shirt is in place pull the front of the belt down. This will anchor the shirt in place.
3rd When you lay on the bench be contious to the fact the the higher you pull your arms up over your head the shirt will ride up on you. This is were a good lift off man comes in handy. Big benchers in denim CANNOT lift big with out a competent liftoff man. So lay down and easily, gently reach back. It will ride up a little, but get your hands on the bar center your rage, then get a liftoff and tell him before hand to follow you out until your signal. You can here me across th egym when i am ready for the bar to let loose from my spotters hands i hollor "MY STEEL"! Then he knows its all me. Until then he is bring the bar out for me.
One more thing i have seen denim blow out and when it does its quick and comes down fast. Have spotters on the side. If you can. Also with denim when you start getting the bar lower it may wanna come up and toward your face when you push it back up, so tell them to watch the bar path. And if it feels like its falling out of groove say take it. Be vocal. But be safe. Denim can and is my friend, but it can fuck you up too!