You don't say if you are using a new or used loader. I'll assume it is used because the factory usually does a fair job of setting the new ones. On my 600 jr. the bottom holes are used. You could try this for easy adjustment: take a factory round and put it in the crimp station. Apply light pressure and adjust the cam and/or crimp punch until you can bottom out the press handle.Kind of like setting the seating depth of a bullet with a dummy round. I do this after I take mine appart for cleaning and it usually gets it pretty close. Then just tweak it from there. Just a note: the length of your shot column can also have an effect on your crimp. If it sits to high in the hull you can also crush the case. This can be corrected by adjusting the wad pressure.