I only have ever done the face (at 45 to 50 degree angle). Then put a very small heel on each flat at 15 degrees or so.
A sharper face angle & heel angle when cutting brass, silver, gold, etc.,,30 and 10 work well.
Just those 2 basic angles on the point will get you going on most materials encountered here.
I do usually blunt the tip to strengthen it @ just under 90 degrees. It's almost microscopic, but it really gives the point strength especially when cutting tougher modern steels w/hammer.
Keeps carbide tools from breaking it's points off too. Brittle stuff but needed for alot of modern gun work.
It's a small sharpening technique not many engravers do I guess. I learned it from Frank Hendricks.
It also helps reinforce the somewhat imperfect free hand freegraver sharpening process,,,,graver in the right hand,,flat stone in the left. Swipe the graver accross the stone to sharpen the face and flip is on it's side to do the heel(s) by drawing it backwards accross the stone. All free hand, the angles are muscle memory if that's the right term. No fixture used.
No power hones back then! I still do that blunting probably more from habit than necessity.
A power hone sharpens the tools now ever since I went to carbide bits in the 90's. Model 21's forced that on me!
I do usually taper the graver back at a very slight angle (just a couple of degrees) on both flats to thin the tip.
That taper may extend from the tip back 2" or a little more on a new graver.
In doing this I change the 90degree incl angle of the graver face to around 100. The slightly wider point makes for easier cutting, flare (bright) cuts are easier to make and the point is stronger.
It also lifts the area of the graver behind the heel up and out of the cut better when turning arcs.
Keeps the area back of the heel from digging in and leaving chatter marks on the outside of an arc, especially tight ones.
Same face and heel angles after the long taper from the point is ground.