How much mole skin I use depends on how loose the limbs are. Sometimes I just put a little square on the end of either side of the slot on the base and/or top of the limb butt. Sometimes I run a strip the length of each side of the base of the limb on either side of the slot. When you do this, be sure the latches still close snugly, but not tightly. If they don't want to close, you have too much material under the limb.
Sometimes, I may put a small piece on the butt ends of the limbs (or at the butt of the limb pocket) to reduce forward/backward travel. Though that usually isn't needed. A few shots and the limbs will position themselves where they want to be on the bow.
Too, it's not always necessary to do both limbs. One may need it. One may not.
Really pretty easy to fix. Just experiment a little. Certainly can use material other than mole skin as well. Various tapes (thicknesses). Good luck.