To make the measurement less/smaller/shorter, you need to screw the die in further.Talk to me like I’m 5. If, when full length sizing, the shell holder is touching the bottom of the die, what do you adjust to make the base to shoulder measurement less?
Conversely, when FL sizing fired brass from your chamber, if you only want to reduce or "bump" the shoulder back .002" to prevent over working brass and maintain "ideal" case length, I use a .002" gage.
I raise the ram fully and screw the FL sizing die down until it touches the shellholder. Then I unscrew slightly and insert the .002" metal gauge in between the bottom of the die and the shellholder. Finally, I screw the die back down until it just touches the gauge, and I can still slide the gauge out. At this point you set the die lock ring and you're all set to FL size with only .002" of bump. Again, this is only for fired cases from your rifle's chamber. You can get as OCD as you want on this, but this is what I do. Here is a video that explains it better.