Yes, the preferred method is the oven. I really would of preferred to use the oven like I did my previous retrofit. However, not everyone has the luxury of a oven that is large enough to accomodate a headlight.
While the heat gun isn't the best way to open headlights, it's the only alternative to the oven. And I wanted to show people that it is possible to do it with a heat gun.
Yes the channels have been manipulated but not destroyed. With the headlight being made of plastic, it's just a matter of manipulating them back to shape. I have yet to have any condensation issues.
*I've also heard of people struggling to open them with the oven, in the other retrofit thread*