After a few months away from my project, the weather and my schedule have allowed me to continue the body work on my '69 chevelle quarter panel. I've asked this question before, but I'm having a real trial trying to get he indented line to look right. It's actually pretty good at this point, and I feel I'm ready for the final skim coat, but I'm concerned that when I apply it, I'm going to have to work that line again. Should I get the line as perfect as possible and just barely coat it for the last time, or not be so concerned and just work it out on what I hope is the final coat?
Thanks,
Rich

The way I do lines is to get them roughed out prior to the skim coat just like the rest. That being that NOTHING is going to need more filling than the skim coat can do.
Here is the trick on the lines. Make them TOO sharp. Make the line very sharp so you can see it. Then after you have this nice straight (or what ever it looks like) line, you "soften" it.

You don't want the skim coat to be cut thru to the filler if possible. It will happen here and there, but the less the better. So if you were to leave it sharp, you would more than likely cut thru. So if you "soften" it by running a block down it with semi cross pattern over it kinda rounding the edge (softening) it WITHOUT messing the line up.

Then when you apply the skim coat, the line will be there and the skim coat will only be fine tuning it. In fact, if done perfectly, the skim coat is mostly filling scratches and pin holes and then leaving a thin film over the whole thing.

Remember, go out much further than the filler with the skim coat. You want it to be almost like a "primer" over that filler and out onto the bare metal (or epoxy primer if you applied epoxy before the filler).

The skim coat should taper off to literally a transparent look. This is with polyester putty at least when sanded with 120 or 180.

Thanks for the clarification, would you also sharpen an indented line like I'm working on? Then use the skim coat to bridge it with a sort of fillet?
A little further down, the quarter panel forms an outside curve. I'm planning on skim coating in two passes, with the two meeting at this curved line. I'm thinking that since it is a change in direction, (and my stripe will go here) it will not be noticed when painted. Is this correct?
Thanks,
Rich