In broad terms, you adjust the sizing die down until it impacts the shell holder when the ram is fully up. I set it down a little further (1/8 turn?) such that the press cams over in an effort to get all the slack out. Some dies have the carbide exposed right at the end of the die. Others have it recessed a couple of thousandths. If the carbide is exposed, it might not be a good idea to have the press cam over. It could crack the carbide. In any event, the die needs to be fully touching the shell holder when there is a case being sized.
Ordinarily, sizing dies are pretty precise and they need to go all the way down the case.
It has nothing to do with your situation but I'll throw it out anyway: I really like using Hornady One Shot case lube on my cases even though I am using a carbide die. It makes the process a lot smoother and easier on the arm.
"No matter how cynical you become, it's never enough to keep up." - Lily Tomlin