What do you like for the targa hoop vinyl? For the dash face and dash top? For the small vinyl pieces on the floor?

I just put the roll bar and sail panel vinyl using the 3M adhesive. It worked awesome. I would highly recommend paying any extra $$$ for the 3M product

I just installed my targa/sail panel vinyl a few weeks ago with a spray adhesive (3M 08090).

I'll install my floor/interior vinyl kit this week (Weldwood 00272) with a brush.

Definitely Dap Weldwood Landau Top and Trim Contact adhesive. It's super strong and holds up to the heat that the dash and body could be subjected to. Unfortunately the smallest quantity you can buy is a gallon. But you can use it pretty much everywhere. With a respirator
https://www.amazon.com/Dap-Weldwood-Contact...38931&psc=1

with Weldwood products. I like to use a small sponge paint 4" wide roller and tray.

How about for the headliner? Mine is sagging

I used Weldwood for my seat upholstery. Good stuff but really strong smell. I started off in my basement and got in so much trouble with my wife. Smells really bother her and Weldwood is STRONG! I haven't gotten in that much trouble since I stained a tablecloth taking apart my door locks on the dining room table.