I just did this on my '90. My replacements came from LMR.
I test fit them first without any weatherstrip adhesive to see where abouts they needed to be. The clips on the top and bottom of the channel weren't very easy to get back on. I didn't end up using them and I'm not sure that they are needed.
The clips/pushpins on the bottom were also a pain. There's an opening in the bottom of the weatherstrip... I centered this with the push pin and pushed it in as best as I could to hold it. It's not perfect, but it holds and you don't see it when the door is closed. I used adhesive and one side and didn't use it on the other. I think I'll go back and add some at some point, but it seems to be holding good so far.
If I had the choice to do it all again, I think I would have left the 27 year old pitted/chipped windshield in the car. The new glass looks great and the windshield trim looks like new after I painted it all, but the headache of the weatherstripping may not have been worth it. The biggest PITA is that the windows don't roll up all the way anymore... I'm not sure I want to get into adjusting them yet. I may just roll all Summer with that top down and say heck with it, lol.
Good luck. Let me know if you've got anymore questions!
Kevin