I have broke too many using the tool and sawing with wire. If you lift at all while sawing, you are stressing the glass and it may crack.

Call me crazy but I like to leave the butyl cool, in my mind it seems brittle and does not adhere as well. Once it is warm and sticky it seems to reseal and not want to let the glass go. maybe I got it too hot and just wasn't careful enough sawing.

My method takes forever but I have successfully got them out. I first just take a utility knife and cut the butyl around the outside edge of the glass, then using a very narrow and sharpened screwdriver, I scrape all I can out of the channel. I then use a tool that is about 18 inches long and holds a utility knife blade and go inside the car and just start cutting the butyl. The long knife won't work everywhere so I also use a regular utility knife. It takes a long time and that butyl if tough stuff. Eventually you can start putting a little pressure on the glass to see where you need to cut more.

As others have mentioned not sure it was worth the effort. Also this was on 68 B bodies so the angles from the inside using the long knife may not work.

I think what ever method you choose and none are fool proof. Patience is the key