We used to use a system for shot handling that went on the lines of:-
Prepare the shot with the correct length of line (nothing worse than descending a shot & finding loads of slack on the bottom)
On the end of the shot rope, tie a 2m long waster line, we used 6mm blue polypropylene.
Shot your wreck.
The first diver down ties the waster to the wreck & blows the weight up on a bag. When the bag comes up, the surface party know that the shot is secure to the wreck. Rest of divers descend.
At the end of diving ops, clip the shot to the transom rings & give it a tug with the boat, the waster snaps & up comes the shot line, no trauma, no damage to boat or back.
You can adapt the system to suit your situation. If it's a deep dive, you can sent the first diver in with a 3l pony to blow the shot & save his own gas. We used to have a lifting bag permanently rigged to the shot, all the first man had to do was unroll it & fill the bag.
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: See rule#5