The Stoney Point tool works, without it you are just guessing with lots of trial and error. As mentioned the course thread pitch of 14 threads per inch makes adjustment critical in order to get long case life and accurate loads.
Just for ease of explaining it say the travel for one turn is rounded to .072",
1/2 turn = .036"
1/4 turn = .018"
1/8 turn = .009"
1/16 turn = .0045"
1/32 turn = ..0023"
As you can see you only need a very small amount of turning the die to make a difference in the headspace.