55 Chevy, Matching upper portion of the cab

[wilberweb]

Hi, guy's
I have a question on Matching the upper cab portion of my 55 Chevy pickup. Does any one have any Ideas on how to mach the upper cab corners just above the doors on the upper part of the cab? What would be the best way to match both sides of the curved section. I am trying to get the drivers side to match the curves on the passenger's side. I have pictures to show what I am working with. As you can see I want to try and match the curves so they are the same on both sides. I was thinking about a profile Gage they make a 10" possibly at harbor freight tools. I have a 4" but it won't cover enough body area to match up the curves.
Any help would be great.

-Larry