I've got some nice green Gravensteins (with a lovely aroma I'd like to keep in the cake) and an old apple cake recipe that I've always made with thick slices of peeled apple. But I was reading a 2005 post (Gordon Wing, are you out there?) which said NOT to peel Gravensteins for pie because the skins just "melt away".
Other factors that may be relevant: the cake is a bundt-type cake which will bake for around 1 1/4 hours. I usually slice each peeled, cored apple into 12 wedges. These apples seem to have been waxed.
Should I keep the apple skins on? If so, how do I get the wax off?