the best place i know to start from is..
find a place to safely spin the tires..
like an industrial complex ect...if you do it on concrete thats even better..
find a clean section of road surface
and do a light burnout..spin the tires while rolling out.
then get out and look at the imprint on the ground..
you want as wide as possible of an inprint.
with an even coloring as it moves to the center of the marks/patch.
if the center is much lighter than the outlines..
then you need more air...add 1/4 to 1/8h pounds of air and repeat..

if you have a dark center of the patch and it fades as it reaches the outer edges..you have too much air..
lower in the same amount..
you are looking for a evenly dark patch across the entire black mark left on the ground.
once you have this jot down all of your psi's
this should give you a really good base to work/start from
right down your psi's and temps if you have that tool...it helps alot.
and start at that point at the track..
thats what i would recomend...
this works for slick tires too..
cheapst