I reckon your in for trouble welding them as they are thin and rusty and your using arc. I had the welding supplies make me an adapter many moons ago that screws into a 9kg bbq cylinder and adapts to my acetylene gauge works a treat and no rental on cylinder but LPG has less heat than acetylene and cutting tips are different. I use LPG cylinders for the house and at the moment they are $88 for 45KG and no rental charge. Much better value than a bbq gas. If you go down this path you might find it easier to bronze a patch on rather than arc welding. It's a shame because I threw 2 good power torque bases out a few weeks ago.
You could always try getting some 1.6 or 2mm arc rods so you can run them on low amps. I get mine from the market 2.5kg box for under $10.
