I have been doing heavy aircraft structural work for 43 years at my day job, and also GA aircraft damage repairs. Hail dents in thin skin 2024-T3 are seldom successful to the level of them being fully worked out, simply because the material is stretched and will not return to its original shape(inny becomes outy). Curved surfaces are a little easier, but access to the back side is required for "spooning", a form of massaging the smooth dents out. The heat gun the car guys use if often to make the paint mailable and not crack rather than soften the metal. 2024-T3 takes 940F to start back to annealed condition, and we don't even need to go into all that. I am very familiar of the Boeing process , and have some experience with that on airliner bonded honeycomb surfaces. In those instances, there is no access to the back side, and the unique tool supercharges the skin and collapses the field generating a very loud bang ..sounds like a shotgun going off when it does. Perhaps someone has a better idea, and if so, Id like to know it!. Most often, lightweight filler and paint are the best option.