hey mate are you from near willyk?
he helped me with advice for my first build. to get that "black grain' you DO need black grain filler, especially for ash. also, he uses Danish Oil, as opposed to varnishes. it comes up with a soft-gloss, like his jazzmaster/tele crossover (i imagine thats the guitar you're referring to?). danish is easy as pie, can pick up a big tin of Cabots Danish Oil from Bunnings or similar for $40 or so. i have limited wood-working experience, and very limited wood-finishing experience, and i found danish oil finishes very easy. i did around 18 or so coats, one every day. all you do is wipe it on with a cloth, sand it into the wood with wet/dry sandpaper (i forget the grit, maybe 400? it has it on the back of the tin), and then wipe it off with a clean cloth. repeat the next day. when i'd finished the coats, i left it in the garage for about a week to dry out and cure. a year down the line, i have not had to alter it in any way, still looks awesome! it gives it that slightly yellowy/browny colour that willyk's jazz/tele master, and his choc/vanilla LP have. almost looks like a vintage tint. very classy.
i didn't grain fill though (i was using black korina), but you'll probably notice that most wood finishes have pretty good instructions, or you can ask one of the workers at the hardware store where you buy it and they will help you out.\
good luck, give the lads here on the board a shout if you run into trouble
