I don't think it much matters where the split in the glazing is. It is not someting that shows and for me water drainage is not an issue as I would die before letting the car get really wet, after all the rust repair I had to do during the rebuild. I am really responding to give my thoughts about the glazing material I bought from Moss or VB (I can't remember which). It was really too thick to install the glass by a long shot. I ended up using a very heavy black PVC tape instead. It would have put way too much stress on the glass and getting the corner screws into the angle brackets was not possible (and yes, my glass is original as is the frame). I simply put the tape on to the thickness I found just right, and then trimmed it after the frame was assembled. It stretched enough to avoid wrinkles at the corners. If sealing the frame is an issue, I suggest a very fine bead of polyeurathane or silicone sealant. Do not over-do the sealant if you think you might ever replace the wind screen. Silicone can be mighty tough to break free and remove. Also, be sure your screws are short enough and don't hit the edge of the glass when you install them. Nothing makes you feel much better than putting the wind screen on after years of work.