do i need to put any sealer along the bottom edge of the back window sill before i put the gasket and widow in?
Yes you must use a sealer in that location, or it will leak right onto the package tray and into the trunk.
I would use urethane sealer...Most of the butyl tape stuff is not soft enough to conform and seal properly in window sealing apps...
Yes, its more like a thick string/rope but...I wouldnt take the chance...If it doesnt seal. You will have to take it and the glass out to re-seal it.
Product looks like this...3M bedding and glazeing compound. This is what you want to use on windshield and back glass when installing it...
I am confused on the subject of windshield sealants. Some say use butyl on the older cars and some say use urethane. Most say "flow grade butyl. http://www.technologylk.com/crl-windshield-sealant-lk-CRL7711.html
could i use both the butyl rope and the sealer, rope between meatl lip and rubber gasket and then seal between the gasket and the body?
The issue with Urethane on older cars, is the car body will flex, and the gasket will flex along with it, if you lock it all in tight, it has no where to go, sometimes breaking the glass.