I never used a shock leader and wonder how many of you use them? I never have been able to cast very far with my 8 foot rod but 95% of the time it is not needed. I normally just tie the double drop rig to my 14 or 17lb. Trilene XT mono line. I also just purchased a 9 foot St. Croix Triumph that I’ll try out next month.
On my small set ups, 15lb mono, no shock leader. On the bigger rigs, 30lb braid, 50lb mono shock leader. I have been cut by the 15lb mono on long casts, with waterlogged hands. When I used 25lb mono, only had a 35" 50lb “rub” leader.
I use the rule 10 lb line weight for every 1oz lead for hard surf casts. If I exceed that (usually do) I use a shock leader. The main purpose for me is to not have the lead and rig break off during a hard cast and injure someone. I certainly agree with the smaller lines cutting you as well.
If your fishing for sharks use about 3ft longer than your rod of 150lb mono. So on a 10ft rod about 13ft will do. About 1 ft on the reel and 2ft out of the tip connected to about 18 inches of wire. I use a sinker slider with a liter than my line coast lock swivel so the swivel will bend out instead of popping my line.