I use spray glue to afix the seal all around the glass. Just spray glass & tape, then after a couple minutes stick it to the edge of the glass all around, then fold it over each side. Overlap the corners & slice through both layers 45deg with a blunted blade...dig out the debris and fold the edges back for a perfect 45 corner.
I like using the original style fabric backed cork tape which seems a little thick at first...except the fabric re-enforcing prevents bunching & tearing and it slides into the frame for a snug fit.
I put a small amount of black butyl sealant in each corner, just enough so it gishes out a little, affirming a complete seal.
*We strongly discourage the use of silicone sealer around autoglass. (I don't want it anywhere near my Model A)
Silicone promotes and intensifies corrosion.
We have enough trouble finding good windshield frames & you don't want those nasty silicone acids seeping into your carefully restored frame.
Butyl sealant is petroleum based and effectively does the opposite by exuding an oily residue which creeps and prevents corrosion.
Extra precautions for you or anyone who cares
1) Trial fit the glass into the frame first and determine if there's enough room for it and the tape
....much better than bending a frame forcing things.
2) Trim the cork to edge of frame when finished, with a single edge razor blade.
To prevent scratching/etching the glass, be sure to "blunt" the corner of the blade slightly on a fine oilstone.
3) You can effectively scrape glue & debris and clean your glass with a razor blade, except always select a NEW blade .
If you follow this rule you'll never scratch the glass from a burr or nick in the blade.
Craig Lewis...Gator Auto Glass est.1992