Preshading White Planes

I'd like some advice on a project that's ready to paint now. At present I'm painting my first white airplane. I've never done a plane with a white belly much less most of the aircraft. (Surprised myself: lots of blues and grays but I've done say a USN three color scheme.) I was going to put on very opaque gloss black because my normal problem is covering up the preshade. I did a little experimenting and I wonder if it will work that way with white. Don't want too much paint just to cover the preshade. I was planning on using light gray primer but I suppose I could pick up some white tomorrow. Would some tone of gray or brown work better?  Very thin black? Blast away and figure it will cover? Don't want to screw this one up. Opinions from wiser heads appreciated.

Eric