need measurement from standard point to mid front wheel

by measuring wheelbase, this tells me you are trying to set caster...if the caster is a little off, its not going to affect tire wear, or anything thats going to put you in a ditch, unless you plan on taking it to the alignment shop at 65 mph, in which case the top of the spindle needs to be behind the bottom, for high speed stability.....
(remember when you were a kid, and turned the handlebars of your bicycle around backwards?)more important is toe(1/8th" in). and camber(i use a magnetic protractor on the face of the rotor) kick the top in about 1/2 degree...