Alain--
I'm a newbie at instrument finishing, so take this for what it is worth...
I am also in a position where spraying is just not an option. I have tried several different things and have ended up coming back to FP'ed bodies and Tru-Oiled necks.
I learned something from the June 2008 issue of Fine Woodworking about creating a wiping varnish from Pratt and Lambert No 38 varnish, pure Tung oil, Japan Dryer and pure spirits of turpentine. The P&L is a bit of a PITA to find, but I now have a quart. I'm going to do a side by side comparo on a piece of mahogany veneer -- FP and the wiping varnish, both over a Z-Poxy pore filler.
I'm hoping that the finishing guru's will chime in here and let me know if I'm barking up a bad tree! Iinstrument finishing is its own world as I have come to learn from following various threads over the past two years. Most of what is applicable to furniture just doesn't cut it when applied to guitars. I'm sort of hoping that this recipe is on the right track as I would like something more durable on the body, but still be able to FP the top.