I have found that treatment with 303 protectant seems to help with wrinkles. Or so it seems - I may be full of it.

But I also second the idea of asking how tight it is. My new BAS top has not even been 303 treated as of yet (gotta get to that) and my wrinkles, once I put the top up, go away in a few minutes.
If it's an old top, and all stretched out, you are gonna have wrinkles. My old Graphite always had wrinkles.