Depends on what you want to do. Lots of traction or enough? Worried about track longevity, or not? I have 108 on my 136" track. 2 studs per section with a repeating V pattern, up the middle only. Want more? Go 2 up the middle and 1 every other section on the outside. But 108 up the middle should be enough for general trail riding. Look at the patterns on the stud manufacturer's website, like Woody's. You don't need a template. In fact, if you do it by hand you will get more scratch lines because each stud will be located uniquely.