Is there an official sequence for choosing whether to spend or cancel an impetuous order and determining the path such impetuous trooper would take? For example do I need to spend/cancel the order before I know if the trooper will run to the left and pull an ARO or to the right and stay in total cover? It seems reasonable that the relative distances/paths could be considered open information but was hoping for some affirmation from the wider community. Thanks in advance for any feedback!
Considering you can't even measure to see which enemy is for sure the closest, I'd go with canceling after figuring out which way they would go (as that's something you can eyeball between turns, anyway).
Also, remember that distances are measured in ORDERS, not inches. If it takes you 2 orders to get there (or a Move-Move), that's what you go with.