If you're going to doubleteam, when do you decide to use the setting "always" vs "if leading scorer"?

I only double always if there is one player who takes more than 50% of teams shots.

I will double if leading scorer when one guys offensive skill set is significantly better than his defenders skill set.

I would also consider whether or not the guy is a good passer, whether or not someone else comes close the the off% he has, and of course what defender I have on him. If their top scorer is facing one of my best defenders I rarely double.

I generally only double team someone if I have to build my defensive strategy around it, so that means it's usually "always."  The big exception is if I have a sub-par defender matched up against a scorer on a team with 2 or more scorers.  In that case I may put in "if leading scorer" to kind of cover my butt in case the opposing coach was paying enough attention to up that guy's distro and try to take advantage.  Usually I'm only doubling a guy who scores a ton but has poor enough BH/Pass to turn the ball over a decent amount if I double him OR the one good 3-point shooter on a team.  In those cases I'll generally go always.  I might take a team that scores 30% of it's baskets on 3s, but almost all from one player, and go -3 but DT the 3-point shooter.  In that case I can't risk only DTing if leading scorer, because he could take 2nd fiddle or just have an off night but still make a couple massive 3s at the end of the game to sink me.  Same thing with the elite scorer - I can't risk the combination of DT effectiveness and maybe a bad night with the RNG making him singled late in the game when I need him doubled the most.

I'll do the "if leading scorer" as an insurance policy if I'm trying a more extreme minus defense against, say someone who underuses a good three shooter. Then if he decides to suddenly ramp up that players three shooting, I'm at least partly covered.