Honestly, it doesn't matter once you get past the beginner stage of trad.
The only distance you need to know is "too far for an accurate or ethical shot". I try not to practice from any given distance very much; instead, I establish my MAXIMUM, then move it forward a few yards to make up for terrain, "buck fever" (nerves, adrenaline) and the like and practice moving around and shooting at various positions and locations within that max. The shot you envision usually never comes, or if it does, it's completely different. Know your limitations and work within them.