Paul; regarding your point #3, reread Bob's post above wherein he states that the lemon oil Mica speaks of is pure extract of lemon skin.

Thanks, Mica.
 
S Wood: My personal experience with tung oil use on fingerboards (16 or so yrs. ago I used Watco Danish Oil Finish - Natural, no colorant)resulted in a sticky fingerboard and gummy strings. I don't what name brand my repair guy uses, but when I get my guitars back from him the fingerboard is not sticky and the strings are fresh. I think his trick is let the oil harden (dry) sufficiently, then he reinstalls the old strings and plays them in so they absorb any stray oil. When he's done, the guitar is great. He also polishes the fingerboard (wetsands)along with the frets, so the board is shiny, smooth and non-sticky with perfectly dressed frets. I'll ask him specifically what he does, and pass it on to the Collective Alembic Brotherhood as soon as I can.