That's typical, especially if you have NOS fenders. Get the upper belt line correct and then put as many shims as you are able in the bottom (probably 3 1/8" shims). Having someone carefully apply a lot of force to the feature line are toward the back of the fender where it is heavily braced will help.

Sounds like you can tighten up your door to quarter gap and still keep 3/16" in the front.