Used to deliver Co2. Both with the big tank on the truck (ever see a guy hooking up a hose to the side of a restaurant? Now you know what they’re doing) and cyl. too. Yes a true 50lb bottle will weigh over 100 lbs. I don’t think you’ll get much dry ice from it. Having serviced those system I can tell you that it turns into a gas as soon as you open the valve and the cloud of by product and dry ice will be pretty much everywhere. I think there are much more efficient ways to strip the body and collecting the by product you are trying to get.
I respect your creative process in an effort to save money. That type of approach does find better ways to do things, but in this case, I think I would factor in what your time is worth and maybe find other areas to save money.