Spring..When a young men's mind turns to rusty nuts.....

[Wayne Henderson]

This only my suggestion. After spending a day similar to your experience, but using far more curses than muscles, I sat down and thought about it.
Next day I took 4x20" rims and tyres down to my local truck tyre dealer who removed each tyre in less then 5 minutes. Using the "mother of all rattle guns" and a air tool like a wedge (fitted under the bead) these 60 year old tyres popped off in seconds.
After sandblasting and painting the rims I had the same guys refit my new tyres and rustbands (which I supplied). I paid for 4 new 20" tubes and all up was $38 dollars per tyre. They didn't charge for taking the old tyres off... this is the bit where I learned something about letting the fellows with the right gear and no how do it... Byford Tyre Service on South West Hyway, Byford. West Australia... good blokes.