Blinddeafmute101 :
The SAE spline system uses the same "basic" tooth thickness for all classes. This is pi/pitch/2. A plug gage checks space width, ans is made so that, when worn to usefull life, would be size to size in a minimum internal spline.
The detail tolerances are in ANSI B92.1-1970, but you don't really need them unless you are inspecting gages. Ordering to that spec will get you what you need.