I haven’t seen the video on Jimmy Blackmon’s method of marking the riser that you reference in your first post, Legolas. I’ll have to look it up. Jimmy is well known for his videos on the fixed crawl, which is another method that is very useful for traditional bow hunting where most of the shots are within the range of 15-25 yards.
The rifleman taught me a method several years ago here on Tradgang that I still use, and I think he still uses too, that is very similar to the method you describe of marking the riser. This method is to use the top of the strike plate to aim the shot, similar to a mark on the riser, but perhaps a little easier to see. Using standard strike plates that either came with the bow or I have put on myself, I find that aiming with the top of the strike plate gives me a point on that is somewhere between 20-25 yards. It would be possible to trim the strike plate until the top was calibrated for a specific distance, like it would be if you make a mark on the riser. However, as long as I know from practice that the top of the strike plate represents point on at 22 yards (or whatever it turns out to be), I can use it to aim accurately at any distance I plan to hunt, from 15-30 yards, simply by holding the top of the strike plate slightly above, on, or below the spot I want to hit. Since I’m not changing anything on the bow or string, like I would if I used a fixed crawl, I can easily change to whatever other method of aiming I might want to use. Also, since I’m not using the point of the arrow to aim, I can use different lengths of arrows without changing anything, although of course arrows of different weights have different trajectories, but this doesn’t change the POI much in the 15-25 yard range.