well 17 people have read your post but no one has replied, so I'll try.

Turning your kite with a bigger bar results in a bigger difference between the right and left lines, therefore you can get the kite to turn faster with a bigger bar. In the good old days small kites used small bars (because they only needed small control inputs to turn) and big kites used big bars (because being so big they're naturally slower to turn).

Often now even big kites come with medium size bars because the manufacturer thinks their kite turns fast enough with a medium bar. They've increased the turning ability of their kite using other factors like having a big wing tip size.

You want a small/medium bar for a 9m (is that what you said you had?). 45 - 55 cm. If you want to turn the kite really fast you could use something bigger, but they get a bit unweildy at those sizes.

Also a bigger bar tends to twist itself to line up with the wingtips of the kite. A really small bar will give you less space to wind up your lines. But now I'm just being picky.

Pulley bars! Well! I've never used them. Basically they're a good way to set up a four line kite to be used like a two line, that is, no chicken loop. Because of the pulley, turning the bar results in big differences in line lengths, and turns the kite super quick. I've heard if you start a turn, the bar likes to get pulled into a full full turn, like over enthusiastic power steering.

I'd stay away from it until you're sure you can handle all the winds gusts through your body/board, with no help from the chicken loop.

Anyone else have anything to add?