It’s been a couple of years since I did mine. From memory 🤪:
1. I didn’t glue mine. There were 4 prong clips that go into the channels to hold in place.
2. Same 4 prong clips.
https://www.sl113.org/forums/index.php?topic=19388.03. Are you old seals original? I would start by copying their cuts. They are angled or even compound angled.
The new seals (window & a pillar) are longer and give you room for multiple cuts just in case. Once I was sure I got the angles correct and the two seals matched I cut the window seal first then matched the top of the A pillar seal. From there I cut the bottom of the A pillar to length.
I seem to remember there is a cap or plug in the A pillar seal that must be removed before cutting and then reinstalled.
Biggest tip is just cut a little as possible at first to get your angles correct. I always leave a little long because you can compress the seal. I took my time and made many cuts to get a nice seal. My seals where not original the the PO did a terrible job.
Do a search and I’m sure you will find more tips and pictures to see what correct looking seals look like.