This is a good topic becasue it all boils down to proper gun mounting.
When I was younger I was told by someone to close my eyes and throw the gun up and and open my eyes and see how much of the rib was showing if any. Most of my guns fit in this range of just seeing along the barels evenly.
Now I never did any trap shooting, just skeet and sporting clays, but I do know that trap guns are built for rising targets.
Since most of the shotguns I use for both hunting and target, and I know how they fit even with heavier clothing on. I don't like recoil pads especially with heavier clothing because they don't let you get that little extra "fit" when mounted.

David