John, sounds like you're going about this the right way I'm assuming that the wrinkles are horizontal, not ~ vertical - if they were ~ vertical, you'd have to slide the top of the liner around to get them out. There is no need for a vac with the overlap liners, and in fact I wouldn't use a vac for any liner if you're only lowering 1/4 of the water - as long as you have 6+" of water up the wall, the vacs aren't necessary.

Good luck with getting the liner wrinkle free

--Ted--