How does one insure that the template prints out in the correct size?

The cowl curvature in that example isn't anywhere near correct. How would you know which end should be at the edge of the cowl?

I suppose if the hole spacing matches the light it's ok but it leaves a lot of room for error up and down


1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)