Puckish: A very simple rule works fine in most situations. If on roll you are 10% (of your pip count) ahead minus 2 pips, you have a borderline double. If you are 10% ahead plus 2 pips, your opponent has a borderline take/pass.

That is of course in "money play". The take point can be different in function of the match score (and the presumed strength difference between the opponents) ; and when one of the opponents has too many checkers on low points.