Heat gun or blow dryer?

IMO, If the hair dryer actually works, why not use it. And if it works you can show the wife then she may never use it again, lol.
A heat gun will likely be a lot quicker though. Best choice I feel. Practice on a couple small sections of tubing over some wire to get the feel.
Open flame from lighter or torch as a last resort. They work but are most likely to burn the tubing and or surrounding items.
Prep for fire control!