Roof rail weather strip seal
I just installed that piece on my '66 a couple months ago. It wasn't too bad at all. I started at the front by screwing in the front screw and worked my way back. I also glued down the front piece that hangs out of the channel where the front screw is. I used a plastic trim tool to push both sides of the seal (inner and outer) all the way into the channel. You'll know once it's seated all of the way. There's a spot on towards the rear around where it starts to bend down that flaps in front of the quarter window. It's hard to explain, but you'll know when you see it. I'm happy to take any photos you need.
I just installed that piece on my '66 a couple months ago. It wasn't too bad at all. I started at the front by screwing in the front screw and worked my way back. I also glued down the front piece that hangs out of the channel where the front screw is. I used a plastic trim tool to push both sides of the seal (inner and outer) all the way into the channel. You'll know once it's seated all of the way. There's a spot on towards the rear around where it starts to bend down that flaps in front of the quarter window. It's hard to explain, but you'll know when you see it. I'm happy to take any photos you need.