The most important angle on a gouge is where the nose of the gouge meets the grinding wheel with the flute facing up. That must always be consistent . Once this angle is established, you can always place the gouge against the grinding wheel and make adjustments and use aids as the others described above without having to purchase angle setting jigs.
I have made standard angles by cutting 1/2” dowels about 6” long on the table/chop saw. I have cut every angle that I can possibly use for pennies.(free if you turn your own dowels).
I place the dowel(just like I would a gouge) into my varigrind(at a preset swing) or Ellsworth jig both at a consistent 2 inch depth so that the dowel is tangentially touching the grinding wheel at around 1-2 o’clock (never greater than 3). Then I adjust the slide last.
Optionally, You can purchase a male and female threaded plastic conduit connectors in HD or Loews for about $2. These can be used with a pvc stop block to fine tune the slide distance as the stone wheels wear.