Supertop fitment questions

Hopefully someone can shed some light on a minor but annoying issue I've found with my new Supertop install.

I installed all the hardware and got the top on with very few problems. The doors all line up and adjusted just fine, they latch easily and seal pretty well. The back window is tight, but it zips in and closes ok. The side curtains however just don't want to zip in all the way. There is about 3" of gap at the top rear corners of each side curtain where the zipper just won't go and I'm afraid of damaging them by trying too much force. I've tried letting it sit out in huge sun on a warm day and that helped a lot but they still won't go all the way.

One thing I did notice was that the instructions specify there should be 69 1/2" from the back of the top edge of the WS frame to the rear edge of the tub, but I can only get 70 1/2". At that, the top is actually pulling the WS frame back enough that my WS latches aren't actually holding anything and I can't adjust the any tighter.

Would that 1" difference be enough to throw the geometry of the top off to give me this much grief? If so I'm not sure how I could get the WS frame to come back any further without removing the gasket betwee the tub and the WS frame and I obviously don't want to do that.

Any idears guys?