Todd, I've glassed the coaming riser along with the deck on almost all my kayaks. No problem with wrinkles, but keep scissors handy to cut a few notches in cloth going up the riser.

By the way, my layup for the cockpit coaming for my last 6 or 8 boats has been:
1) Fillet the outside riser to the deck
2) Glass deck and outside riser (one piece of fiberglass
3) Glue strips to make the rim (using Kurt Maurer's removable rim method that allows easy cleaning up of the underside)
4) Glue on the rim
5) Glass the riser inside and top of rim
6) Fillet the underside of the rim

I no longer glass the underside of the rim to the riser. Fillet only. Never had a failure, so I'm sticking with it.

John