QUOTE(beondwacko)
That would not work in this application. The dent on this tank is on a curved peice of metal. It will never regain it's original "Memory" of shape. Those things sometimes work OK on a flat panel though.
Get your present tank fixed. A PDR ( Paintless Dent Repair ) guy might be able to "spoon" out the small dents you have.
Funny, it took the dent out out of my tank. Was about the same size as the one pictured in the eBay ad. In fact, in almost the same place. Bought the kit for $9.99 and did it 4-5 times before it finally came all the way out. Each time it improved slightly. Now is it 100% perfect, no. But its so minor you really have to be looking for it and be in the right light.
As for paintless dent removal they go behind the panel and then pop it forward, but since gas tanks have an inner and outer shell, I dont know how they would get between them - unless you can get between the shells by removing the gas filler lid. Somehow I doubt that though.