I saw your post this morning before work and been kinda thinking about it all day. You're where I was 25 years ago. My first thought would be try harder to find someone else to do it for you. But then I remember that I really like sandblasting [not too bright]. Keep in mind this is only my two cents worth and that aint worth much. The most common blast media around here is silica sand, the stuff that gives you silicosis, a fatal lung disease. I get it from a supplier, but most building supply stores handle it. Usually runs about $5 to $6 a hundred pound bag. The blast pot you mentioned is good for small projects but can do larger areas depending on your time and patience. The size of the nozzle or blast tip is what sets the size of the area being cleaned. I once did the inside of a steel box [tandem dump truck size], with one of those and it took two days. The really important thing [see silicosis above] is to have completely clean breathable air at all times. Until i got a pressurized hood, I used a charcoal type paint mask. They're hot, smelly, and expensive, but they keep you alive. Don't go with the cheap paper dust masks, they let too much dust get by. Now the really expensive part, the compressor. If your compressor can't handle a steady stream of air at the blast nozzle, it won't work. You will run out of air, waste sand and time and get frustrated. Been there and done that many times. I don't have any idea what cfm you'll need, but a bare minimum for pressure is 80 psi for a decent job of blasting. Keep in mind there's a lot of different blast media, and different ways of doing things. This is some of what I've picked up over the years. Sorry for rambling, but that's what happens when you get old.