Butyl? You don't mean THIS, do you?
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That stuff is for windshields and back lites where NO rubber gasket is used.
What you need is the NON hardening bedding compound. I've seen factory manuals that state to only apply it along the bottom and up each side 12" and I've seen other manuals state that the compound should go all the way around the "fence".
I apply it on the fence/channel, then slide the rubber gasket into place, holding it still with strips of tape. Another in consistency that I have read is where to start with the window. I've read to shove it UP into the upper channel first and work your way down, but I've also read to get the bottom set first and work your way up.