"Disposable" welding gas bottles are a perfect size. With regards to using a bigger one on the basis that you get more is a bit difficult. Unless you were to go for something really big, your benefits are really small. I have about a 10l tank, and will run much smaller next time.
Mine is charged from an air con pump, but have a t max plumbed in as spare. No complaints about them, have killed one but that was understandable because of how it was treated !
G