For Remington hulls:
The Claybuster CB0178 (silver WAA12L) is an excellent 7/8 oz wad. I also use the CB-4100 Lighting wad which is a slightly lower pressure wad. The Alliant site says use Rem 209 primers which is a quite a bit cooler than Fed209A's (my favorite primer).
I actually use both these wads with a slightly higher charge of Red Dot (18.6g) for 3/4 oz loads in 12 gauge Remington Gun Club Hulls. They break the clays with authority on the skeet field and 16 yard trap. I only shoot in the 21-23 range on skeet, but I almost always kill the 3-4-5 stations, my mess ups are on easy stations and it's more of a mental thing.
The problem with Federal Hulls is that they are straight walled hulls and tapered wall wads can leak powder around the base, but I've found that not more than a few flakes do that if the wad is pressing against the powder. The other problem is that the Fed hulls are bigger than Rem hulls (and a lot bigger than Winchester hulls) and take more powder to get a decent pressure where you don't end up with inconsistent velocities and "bloopers" in cool weather. The Fed209A primer would help you in this case.
If you need to use the cards at the bottom of the 12S0 cups in order to avoid "dished" crimps or holes in the crimp, you can set the pre-crimp down a bit more as well as the final crimp. If you end up with swirls, that's OK, it's better than a dished crimp. It will raise the pressure a bit, but unless you are in the 11,000 psi range, you won't have a problem.
You might go over to shotgunworld to ask the reloading guru's there. They are experts at this stuff.
Good luck.