Yes the bottom, cup shaped, over powder, gas check portion of the wad, the ones I am finding are not totally dished out, the bottom of the cup has a convex bump or is flat.

Really the biggest problem with them is they are wads for tapered cases such as the Win AA's and Remington's. They have a gas check that is smaller in diameter than the ball so have no chance of riding on the bore and keeping the ball in the middle. They mic out at .685 my bore is .730 and the ball drops out at .718 The one and only Federal wad that I have (stolen from a factory slug load) is .730 wide and when I push it trough my bbl rides on the bore and holds the ball nicely centred in the gas check. That particular was is a specialty one and is not offed as a component.
I will rustle up some regular Federal wads they may be the ticket to hold the ball if AA's don't pan out. I still need the smaller gas checks off the AA's for powder seal in the Remington hulls.
More testing required LOL!!!