finishing a neck (rosin varnish)

i'd like to get a guitar made by someone (possibly usacg) and finish it myself. Finishing the body seems easy enough. The neck is another matter. I don't want to get finish on the fingerboard.

Ideally, i'd like to use rosin varnish. i like the idea of a non-plastic finish, especially one with a long tradition of use with musical instruments.

should the back of the neck be finished before applying the fingerboard? if this is done, how best should it be done? it seems taping the area where the finger board is to go, and varnishing around it, might create a "ridge" of varnish.

any ideas?

What type of wood for the neck? All maple, maple with rosewood fretboard or other?

i'm hoping to get a cherry back w/ an ebony board.

I wouldnt finish rosewood or ebony fretboards, you would just oil them from time to time, when you change strings and such, so if the neck comes in two pieces without the fretboard attached, finish the neck with the varnish then attach the fretboard. If it comes as one piece tape off the fretboard, just the fretboard, the side of the neck where the ebony and cherry meet leave exposed, than apply the finish to the neck. I can't see a ridge forming unless you tape off the whole fretboard and are going to be doing a tremendous amount of coats. 10-12 coats is plenty, though I think 3 coats, sand level, 3 more coats and you would be fine. The less finish on the neck the faster the neck. Make sure you sand the neck really smooth before hand if it isnt already.

The neck needs to be fully constructed and finish sanded before any varnish is applied.

Once it has been constructed, finish sanded, and prepped. I would mask off the fretboard, and apply the varnish. If a slight finish ridge is present, it is extremely easy to soften the edges and blend them into the fretboard with a little light buffing.

Violin Varnishes and Shellac are commonly available finishes, and fairly easy to apply.

I think I have two quartersawn cherry blanks yet. I think they would look awesome with an ebony board.