Sixer, with 7/8oz you can cut off the inside layer just short of the fold-over where the buckle is attached, allowing room for the prong slot. This way no skiving is required, and 7/8 is plenty to support the buckle. Several "notable" belt makers do it this way.
Sometime the wrinkles happen because the two layers were not stretched out evenly against each other when gluing them together.
When I'm making a 1-1/2" belt, I cut the inside layer to 1-3/4" so I can then trim off the excess after the glue is cured. While the edges may be even and flush, they are still quite porous and rough. I take it to the belt sander and smooth the edges using 220, then 400 grit belts. This makes the edges very smooth and makes burnishing a lot easier and nicer looking. When a good job is done at this stage, you can't see that two layers have been glued and stitched together.