I've been using my little Smith torch for 35+ years with no real problems for a few years I was cutting at least 50 tons of steel a year.
My regulators (brooklyn I think) are so old I had to buy an adapter for the gas one to adapt to modern female gas/propane/acetylene tanks.
They still have the original beveled glass lenses in them.
You do not need a special regulator for different gasses just the cutting tips are different.
Propane tips for my Smith are only about $15.oo I just picked up another complete Smith rig for twenty bucks from a friend who had 3 sets and it is like new guages and all.
I pay $50. to fill a 100 lb tank of propane and that will probably last through 10 to twenty full size tanks of oxygen at about $26 per tank......I own my tanks even though I just exchange them.
My paper work is worth the current cost of new tanks.