I posted the calculator in my signature. It's shared in google docs

I haven't tested crit damage since the KI patch. Too busy leveling when I can vs testing so far. Colton's arcane ability says it lasts 6s. Robots 40% crit buff is only 3s, but Colton gives 15% crit to the party instead of 1 person. So the 15% shoul last 60-75% of cool down.