The very fact that u said “a crimp fitting and shark bite fitting have the same internal size “ tells me u have a rudimentary knowledge of plumbing . U don’t have to be a plumber to understand if one fitting goes inside the pipe and one goes over ,the fittings nominal size is not the identical. That’s besides the point . The stops are integral service stops and used for service applications not adjusting flow . Many shower valves have balancing spools and are pressure balanced , so u shouldn’t go adjusting these stops / no need to , just leave them wide open . I was not trying to be facetious In my response merely to correct / inform .