Oxy/Fuel bottles - Buying, renting, exchanging, etc.

[Mike00]

Hello all,
I'm getting ready to try my hand at oxy-acetylene.
As far as equipment, I found an old airco with a few cutting heads, each with tips plus a few extra, 4/5 welding/brazing tips and a rosebud off ebay.
Also got a set of old rebuilt regulators, and brand new checkvalves, flash arrestors, and grade t 1/4" hoses.

I do not have either bottle.
I don't know if I should buy one and have it filled? rent one? find some empties to exchange?
What are things to look for before purchasing cylinders? besides excessive rust. Are there certain sizes that major facilities won't touch?
I'm also tryin to decide on bottle size. for a given refill, how much of the charge is per fill and how much of the charge is per cu. ft. or pound?

I found a cylinder sizing chart, Are these (left size) generally what people use at home and small shops? As I understand the MC tank is different and takes a different regulator.