"This is good stuff,you cut an empty shell,Where?if you got too much volume after you weigh that specific gun powder then you cut a little more,how much?"
Let's apply a little logic to the process here...
Which is easier:
A) randomly cutting the shell and hoping that you get what you want?
B) Or measuring out the amount of powder that you want (using your scale), pouring it into the shell, marking it carefully, trimming it, and then testing it to make sure that it repeatably dips the amount of powder that you want?
Unless you're a complete and total dumbass, the obvious answer is B.
You start with the known quantity of powder, and if the dipper you made dips heavy, you can either use a file or a lathe type case trimmer to remove excess brass to get exactly what you want.
I said this before, other people have said this, and I'll repeat it...
EVERY mechanical powder thrower on the market is nothing more than a more complex version of the powder dipper.
RCBS Little Dandy or Uniflow, Lee Pro Auto Disk or Perfect, Lyman 55, Belding and Mull, etc. etc. etc.,