I use a Foster set up but I only do my 30-06 and 22-250 cases
since they need the added accuracy down range.

As mentioned good measuring equipment is needed......
and a little bit goes a long ways, don't go crazy removing brass from your cases.

There is inside and outside neck trimmers so you will need to read up
on what and why each is done or if needed in your quest.

Some prefer one brand name case over the others but just try
to get a lot of one type and stay with them, for best results.

Trimming is only part of the accuracy program.
Primers, bullets, powders, OAL and fps are the other parts of the puzzle.

Have fun.