I used a similar system when I had pretty bad RSI over a decade ago but it was a bit different - basically you would hit a keyboard shortcut and it would draw divide the screen into 4-shaded quadrants, you would type 1,2,3,4, and then it would zoom on that quadrant, and divide it up again into four quadrants. Rinse and repeat until the cursor position was at the position you wanted it.

At any point in time, you could hit escape if your mouse was at the precision level you wanted. It actually worked pretty well.