Tried searching but couldn't see an answer. So you get stress before or after you get to trigger Temmins ability? For example of you tallon roll can you still boost before the stress?

Temmin's trigger is after the "Check Difficulty" step, which means you would have already gained 1 stress on a red maneuver or removed 1 stress on a blue maneuver.

Primed thrusters Temmin it is then.