I personally don't hesitate to use Bullseye for max loads published by Alliant.
I do hesitate to use Bullseye for max loadings, particularly in the .40 where pressure can spike quite rapidly with small changes in COL or charge weight. If you're contemplating max loadings, then there's really no reason not to reach for a different powder rather than trying to push he envelope with something less than optimally suited for your end goal.
Power Pistol is pretty good in the .40. It fills the case, meters well, and it provides top velocities across a variety of bullet weights. If you can't find Unique then another great power is Universal. It has a burn rate near identical to Unique, but meters a lot better and also burns cleaner. Those three in that order are my preference in the .40: Power Pistol, Universal, and then Unique. YMMV