For the primary bevels I took 1" square stock and gound the ends to known angles. Think of it as a 3 inch long block of steel, with say 7° angle on one end and 6° on the other. Did this down to 3°
So when I'm hogging metal off of a blank I start with the 7° dependingon blade width. I score the center of where the edge will be. Lay the angle block flat on the work surface and use it to push the blade in to the belt. Once the flat is ground to about half s dime thickness away from that center line I switch to the 6° and so forth till I'm at about a high saber grind. Go free hand from there. Lets me keep things more even.
Anyway, you could probably do this same angled guide block principle for the edge grind itself. I've just gotten a feel for cutting the edge bevel over the years so never looked in to it. And steel on steel or even iron on steel can and will scratch up your blade flats as you drag the knife across it.