I have lent my dent risers to several members of the board. They do not wear out and when I am not using them they just collect dust. I have the 12, 16 and 20 gauge versions. Bought them off ebay at a very decent price. They have paid for themself many times over.
Your suggestion to use light heat sounds reasonable unless too much is used. Then you get to learn how expensive it is to relay a rib or two. You are right that they need a light touch and you need to take your time. I do not do dents for others. If I bugger up my own barrel it is my loss and no one elses.
