The first piece of advice I'd give is:
DON'T use the term "three-roll position" to describe a position that USUALLY bears off in three rolls.
It never ceases to amaze me how I can give someone this advice over and over again and they'll ignore me repeatedly.
A three-roll position is one in which (1) you bear off in a MAXIMUM of three rolls, and (2) every doublet saves you a full roll.
Consider the position below.
| White | 7 |
|---|---|
| |
| Blue | 10 |
| GNUBg Id: NwAAwB4AAAAAAA:cAkAAAAAAAAA XGID=-BD--------------------bc-:0:0:1:00:0:0:0:0:10 | |
A simple three-roll position, right? Wrong. Snake eyes don't save Blue a roll, and if Blue rolls 1x 1x 1x then he won't be off in three rolls. It's still D/P, but it's only a 1.03 pass as opposed to a 1.15 pass. Seemingly small details like this can make a big difference in equity.
The best way to get a feel for this is to set up a few positions where White has a true three-roll position, and Blue has something that you're tempted to call a three-roll position but really isn't. Then pay close attention to what the bot says the equity is (not just whether it's a double or a take). Repeat the exercise with White having a pure four-roll position. After you study a few dozen examples, you'll have a good sense for how many misses translate into how much lost equity.