I am in the process of pulling off the windscreen on my Mark 1 BN7. I have in hand a new glass, the rubber sealing strip, the corner brackets with screws, and a tube of Permatex "Flowable Silicone Windshield and Glass Sealer." The instructions in the shop manual--and I find some of that information curious--does not mention using a sealant when installing the glass. Granted my car will probably only see water when it gets washed, I'm not sure whether it is necessary to add sealant. If it is, I assume one would apply it to the rubber seal as the glass is being pushed down into the frame. I am much aware of the past discussions regarding the shims (one in my car) and the risks of cracking the windscreen. It isn't mentioned, but I assume one has to trim the seal a bit at both both bottom corners. For the record, I have had the windscreen assembly out previously, and thus far I have removed the four windscreen screws at the top corners---all were nicely rusted tight and required lots of attention before coming out, two sans their heads.