For those of you who are reading this thread, I'll take it one step further.
I wanted my old badges off and the surface clean so when the new badges come in next week, I can just put them right on. If you watched the above video, I'll add a few tips to it.
First, use at least 8lb test fishing line. Anything less will be frustrating.
Second, I didn't have a heat gun, but my wife's hair dryer worked just fine on high heat, low fan speed.
Third, you'll have a lot of left-behind rubber tape stuck to your tank. Douse it with a little WD40, then go at it with your finger or thumb nails. Be patient.
When most of the thicker rubber tape is off the tank, take a rough rag like an old towel, and dab lacquer thinner onto the area, scrubbing lightly. You'll have to do it about a dozen times or more, and keep changing the spot you use on the rag, as it will get black tape gunk on it. Rub lightly and eventually all traces of the old adhesive will vanish. I don't know how lacquer thinner will work on the flat tank colors (without a clearcoat), but it did no damage at all to my tank, and believe me, I checked it closely as I went to make sure the lacquer thinner wasn't damaging the clear coat. It didn't.
Once all traces of the old adhesive are gone from the tank, use a mild soap to clean it, then rinse the area well and dry it off.
Your tank is now cleaned and prepared for the new emblems/badges.
Like most adhesive tapes, it's a good idea to clean and prep the area with lacquer thinner right before glueing the new badges to the tank. And if you have some 3M promoter, use it after the lacquer is wiped off and dried completely. This helps the adhesive tape to stick all the better.