In all honesty, my advice was intended for someone who wants to develop "mad skillz", starting from ground zero. I've done enough wet-sanding of various items over the years to prefer media-blasting hands-down over all other options. However, I didn't know what the OP was trying to achieve, which is why my advice was directed toward someone using the frame-painting experience as an opportunity for skill-building... Depending on the goals and budget, powdercoating ROCKS, but the OP actually bought paint to spray the frame with, so I felt he deserved an answer that addressed what HE wanted to do, not what I would prefer to do under the circumstances, working on MY motorcycle...
That being said, the other replies are certainly valid; I live near a media-blasting facility, and all I can say is, I WANT ONE! I mean, these guys do EVERYTHING; I first learned about them in an issue of "Hot Rod" a few years ago, and was VERY HAPPY to find out that they're just a few miles from my front door. The media really isn't abrasive enough to eliminate heavy rust, but it removes paint very well, and it WON'T stretch or warp the sheet metal in the process.
Sooner or later, I'm going to have to repair a leaking gas tank, then repaint it. I already have a replacement tank, so if I ruin this one trying to salvage it, at least I'll have learned what NOT to do the next time. The tank will be my guinea pig; if it survives the repair process and holds fuel without leaking, I'll repaint it and use it. I can't do bodywork to save my life, but that doesn't matter; I'm more concerned with making the tank usable again; if it happens to look like shit when I'm finished with the repairs / bondo / painting process, I can live with that. In fact, I'm willing to rework it fifty or a HUNDRED times, just for the experience of doing it, and building my own skills for the future...
I'm looking forward to seeing those pics, LL; I haven't used the epoxy paint yet, so your results will probably be similar to mine. JRK5892 does PRO quality work, well beyond anything I'll ever be capable of, because I have poor depth-perception. Most people can spot flaws or imperfections in sheetmetal and paint; those same surfaces usually look perfect to me, and as an old body-and-fender man once said to me, "If you can't see it, you can't fix it"... over the years, I've learned not to let that bother me. My repairs suit me, and I can live with that, but obviously, I'll never be known for my skills doing cosmetic restorations... so I read these threads, and I sit here drooling over the quality of the work I know I can't match...