I don’t use a heat gun on mine because it’s harder to control the temperature of the boots. They really don’t need to be that hot, just warm enough to be pliable. On a hot day even setting them in the sun for a couple hours should work. Making them super hot doesn’t continue to increase the pliability.
I wasn't saying it's a bad product, just that the guy was being a jag and not trying to help a paying customer to use their product. He just kicks the can down the road and tells you to use something else. Not good.