Hot Rods '31 coupe glass installation

Before I go and jump off the cliff by doing something dumb, I thought it would be good to ask what everyone has done to seal the quarter/rear glass in a chopped 31 coupe.
Factory was a U channel and there are similar universal pieces available. Or is just as easy to urethane these pieces in place since they do not move?

 

We urethaned em in on the 32s and 33s we built

 

Only bad thing with urethane is Model A's have a lot of body flex.....and replacing a cracked glass that's been urethaned in is a bitch. I used 3M Butyl Strip-Calk. No leaks, no runs, no errors.

 

Thanks fellas. Given the condition of the roads we drive on up here I may try the Butyl strips.

 

You can get universal rubber channel. Put them in right. Cutting them out after urethane is a bitch.