To take out the glass, you've gotta just unbolt it, remove the front rubber cover thing and just "massage it thru the hole, unless you are replacing the weatherstrip as well. Removing this helps. When replacing your guide bushes, unbolt the lower track completely as this makes removal and re-installation easier, as you only have to slide it back onto the guides and use the winder to guide it into position to re-align the bolt holes. Do these 1 at a time and do them up finger tite until both are in then tighten as normal. Clear as mud. I did this job on my 68, including weather seals and it only took an hour or so, and I'm fat and don't fit in the back real well! I hope this is of help. Phone (02)49327180 if u need a verbal explanation!
Cheers, mate!and good luck with it. Ron B