Hi scoutbrewer,
If I’m reading this right, you completed your lift panels and have installed them to the roof and camper body, is that correct?
If not, do you still need measurements on where to attach the lift panel top piano hinge to the roof, or did you get that sorted out?
Have you lifted it up, and closed it, one end at a time, to make sure it sits where it is supposed to when closed, and everything lines up? If not, you might want to review how I set mine on during that part of the build process. Making some cut to length boards to rest the the top lid on while attaching to the camper body was a big help to ensure it attached very level.
https://www.wanderthewest.com/forum/topic/12116-full-build-reconstructing-a-1981-grandby-into-a-custom-hawk/page-12
Next, in your question on where/ how to attach bungees to the side liner, are you referring to the @3/4-1” wide flat elastic that attaches behind the lift panel on one end, and to the side liner on the other end, to pull the side liner in when dropping the roof?
If that is what you are referring to, then the way I thought it would work, and how I did mine, was to pop rivet one end, with a folded over end to ensure it didn’t tear out, to the the center piano hinge on the lift panel (replacing a pop rivet that was already there), and do three elastic straps/bungee’s across the width of the lift panel, spaced apart enough to pull the liner in when closing. On the other end, when attaching to the side liner, I think I tried to fold it again, but can’t remember. I felt for the hinge through the vinyl material to match where it should fold, then carefully drilled a 1/8” hole through the side liner, and used about a 1/8” x 3/8” pop rivet with the head on the outside of the liner, going in to the side liner, then through the elastic strap, then through a small aluminum washer made for pop rivets, before crimping the pop rivet tight. It has worked very well for me. I found them at one of the box stores in a small pack, but for reference here’s an Amazon link.
https://www.amazon.com/Magery-Aluminum-Backup-Washers-Diameter/dp/B0897142XZ/ref=sr_1_9?keywords=pop+rivet+washers&qid=1665341029&qu=eyJxc2MiOiI0LjA4IiwicXNhIjoiMy43NSIsInFzcCI6IjMuMjgifQ%3D%3D&sr=8-9
Lastly, here’s a link to how I installed the side liner. I made side liner height such that I could tuck about one over the 1” aluminum tube of the roof, and then allowed the aluminum roof top to go over the side liner, and fold downward. I attached the vinyl side liner with 18 gauge staples as I went around the perimeter, trying to make sure it didn’t bunch up anywhere. It also was very very helpful to measure and mark 1 inch along the top of the side liner prior to start ting the install, so it was uniformly even. Then I folded the aluminum roof top skin over the frame with the side liner tucked inside, and again stapled that down at about 8 inch increments along the side, before attaching the the trim ring over top with screws.
https://www.wanderthewest.com/forum/topic/12116-full-build-reconstructing-a-1981-grandby-into-a-custom-hawk/page-15
Hope this helps, but just think things through, and a lot of this is somewhat intuitive when you study the process out in your mind.
Good luck, hope it all turns out well. Share photos if you can. I forgot to take pics of the bungee straps being attached behind the lift panels when I did mine, or I could have offered that.
Poky