It's probably easier to watch an 8 minutes video on your smartphone than to practice draw shots from different distances and with different targets for hundreds of hours
The draw matrix is a tough drill. Without the stop shots I am about 60% at the moment on most of the draws from the matrix challenge. (But I am very positive that I can pop it up to 90% in a few weeks with my draw workout and my goal is definitevly to post a video with a score of 85% (so I have 180+ in both challenges).
My workout is 10x same ball (same distance to cb, same draw distance) for about 10-14 different combinations and all about being able to repeat it constantly. Building muscle memory, practicing hitting the CB on the exact same spot and being able to test "the interchangability" of CB-OB distance and drawing distance. (Your formula is about just adding these two, so 3 diamonds CB-OB and drawing 2 diamonds is about same stroke as distance 4 and drawing 1 or distance 1 and drawing 4.) If feel like on my older draw more spin gets lost with CB-OB distance.
But I found out that the draw from BU I (last position, 6.5 diamonds between CB and OB and drawing 2.5 diamonds is the same as drawing from same spot but with CB on 2. diamond (5 diamonds CB-OB) and drawing 4 diamonds. (that would be acutally spot on with your formula - but having this draw in my workout mix I will improve on the draws for BU I so I can finally steal your magenta highscore in this (BU I) challenge.
If it's true, one just needs to practice 8 different draws (for a sum of 2-9 diamonds). Shouldn't be that hard
I am curious if I will stick to the workout long enough for the mentioned improvement. Life has a tendancy to get in the way of such optimistic tough goals (especially having the challenge already finished for me

). Also I am getting older and need a more physiological way for all the hundreds of draws. (Had lateral epicondylitis (tennis ellbow) last time I overdid it with the 9 diamonds draws from BU I

)