I'm terrible at putting numbers on distances ("judging yardage"), & so I've developed my shooting style so that it isn't required. Call it instinctive, subconscious gap, or whatever ya want, it works good for me on 3D & even better in the hunting fields.

I can't put a number on my effective range, & I'm sure it varies according to the situation, but I know a dead deer walking when I see one.

jeffh, I don't suppose my post has been much help, but the crux is that experience has taught me to always wait for that 'can't miss' opportunity when bowhunting. Even if you don't heed advice well, if you stay in this long enuff I bet it (experience) will teach you the same thing.