I have aligned dozens of Mustang II front ends and these are the specs I shoot for for a manual rack.
Camber -1/2 to -5/8 both sides
Caster +2 1/2 LF +2 3/4 RF
Toe 1/8" In
You should see a marked improvement in driveablilty with these specs. If you have wide front tires you may want to kick the positive caster back a bit to about 2 degrees left and 2 1/4 right.
Where are you located? Maybe I can set you up.