Lol, I'm hardly seasoned, I just started loading two years ago this month.
And no, it's not a joke.
Here is a picture for an example. This is my RCBS carbide size die, shellholder, and a piece of new Starline 480 Ruger brass on my Hornady LnL single stage press. I have inserted a small piece of paper between the shellholder and the die on the left side to show the placement. On the right side you can see a bit of light between the shellholder and die.
View attachment 925180
The gap between the die and shellholder in this picture is acceptable to me for a straight walled case, and gives plenty of neck tension. BUT, with a tapered case such as the 9mm, this is too much space and may not give sufficient neck tension to prevent setback. If this were a tapered case the die would need to be screwed down a bit more.
About the press "springing" or "flexing", I'll try to explain. The die in the above pic was setup without a piece of brass in the holder using the paper method. The paper would not pull out. Inserting a piece of brass into the holder and raising the ram to the top of the stroke the same piece of paper will freely slide between the holder and the die. This is due to the resistance of the brass moving into the die, which removes any slop in your linkage, ram, etc..., hence the "springing" effect.
Setting your sizing die on a single stage this way will prevent the ram from crashing into the die, which in my opinion only accelerates wear on your press and die.
Again, this setting gives me plenty of neck tension on straight wall cases, but would not be sizing down far enough for tapered cases.
Hope this helps!
chris