Acoustic Guitar Construction

Have you set the neck to the body per the instructions? And tweaked the neck and sound-board per the instructions? If so you are ready to position the fingerboard install pins and permanently glue it to the neck, let it dry then do the shaping. It sounds like you are trying to add an extra step?

Ken:

I haven't set the neck yet. I can't do that until the neck is approximately the correct width at the body since that is where it
has to fit the neck. Tony has come the closet which is wing it and get it close enough. The situation is that my neck is about 1/2" wider than the fretboard at the neck joint. If I were to fit that then it wouldn't fit when it's the correct width. So I have to get it near to the correct width before I can fit it.

Why not? The width changes none of the important contact points.

Slim - don't know if I'm answering your question or not, but - you can trace your fretboard outline on the neck and sand to that line before you do anything else; that may make you feel more comfortable with this situation and it won't hurt anything.
Then, you can work the cheeks to fit the neck to the body in the usual fashion.
I think you're saying that at the neck joint you want the neck and the fretboard to be the same width. Right on.
Dave

If we are talking about a kit neck, just use a straightedge or fretboard simulator to check everything. Final shaping is done with the fretboard on. Setting the neck angle etc can be done any time. Stop worrying and start building. It's really less complicated than you are making it.