Kite Control Bar Length?

[Rick McClain]

Hi,
Does the size of a control bar vary with the size of the kite? Does a four line "C" kite need a different bar than a "Bow" kite?
How do I determine how long a bar I should get? I have a 19.5m "C" kite that I need a bar for. If I get one for that kite, will I be able to use it on a smaller kite? If so, about how much smaller? Will it be usable on a "Bow" kite?

Thanks