: I found that if I do the epoxy precoat before I do the filling then there is
: no discoloration of the surounding area. You still have to remove the
: epoxy on the surface but there is no penetration.
: Earl

That should work well. You might run into problems if you have to sand off any putty and sand through the precoat. Sometimes this can cause a variation in color. Make sure you sand to the same final grit to minimize any variations due to accidental sand through.

If you are trying to be super-perfectionist, the best way to assure even color is to make sure everything is treated the same way at approximately the same time.