I'm basically taking my first guitar.(a dean vendetta xm) and am making it into a good guitar. i already got the action set up PERFECT. And i'm putting a zackk wylde emg 81-85 pickup set in it. But i wanna sand the neck down thinner cause its to thick. I know once i sand it i need to put tung oil on it. but i dont know how much. and i dont know how thin i should sand it. like i have a charvel model 6 and it has a PERFECT neck and i wanna get it to that. But i dont wanna risk sanding it down to the truss rod. and if i sand it will it warp cause theres less wood to keep the strings from bending? and what sand paper grits should i use and stuff like that. I prety much need a step by step guide. So if you'v dont this to you neck could you help me out?
Well, you can probably get it to the same size as the charvel, since trussrods really don't differ depth wise too much I believe.

If you want to check the depth, go near the base of the neck and drill a very small hole until you reach the truss rod slot. Try not to drill through the truss rod. Also, if it's a bolt on, do it on the heel so you can't see it. That's if it's a double action rod though... I am pretty sure you'll be alright.

Sandpaper will take forever. Start low grit and work your way up. 60 grit can do quite a bit of hogging depending.

It sounds like you're getting in a little too deep. But with a little research, you will be alright.