I would not install anything permanently like that. The cover on my boat that fits the bimini top that came with the boat, has a ton of bad snaps and the only real way to fix that is costly...i.e. drill out the snaps and replace or repair the hole. I know there are guys here that will say there are alternatives... snap extensions, etc, but, there has to be a more cost effective way.
I would also ask on THT, might get more responses, but the real experienced responses will be here.
May not be a better way than snaps on the fiberglass, just saying what I am seeing here, so when I remove the snaps after the top goes in, I plan to repair the hull then get a cover that uses bungees. May not be an option for you, not sure how or what you are connecting the curtains to, but if there is a way... these guys will know it.
Hrm, come to think of it, there may be a per-manufactored solution that maybe clips onto the window. I know most the GW I have seen had curtains on the windows.
R