Chop top help

[ace of shades]

I got a call from a friend asking me to help him fix the previous owner syndrome. The problem we ran into is on his 67-72 chevy chop top the window has been urethaned in and it fits like a glove - an extra large glove on a small hand.





The orange line is were the pinch weld is now, but it needs to be brought out to the green line. It seems that when the window was in it was set in place with over a half inch of urethane and left an unsightly gap with an unfinished look.



Red needs to be moved in
Green needs to be moved out
White stays

I have tried hammering on it, duck billed vicegrips, crescent wrenches and nothing seemed to move it very far. My last resort is to make a buttload of relief cuts and moving it to where it needs to be and go from there.

Does anyone see, or know, of a better way to tackle this problem