I always try to put meat as high as possible; works good for me. If I'm smoking different sizes of meat, a put the thinnest portions up high, and the thicker cuts as close as possible below. That allows the thicker cuts to absorb the heat closer to the smoke box.
You might check some of the jerky posts on rack rotation. You may want to during the initial higher-temp phase, but I bet you won't have to when the temp is low and the fan is on. But I'm just guessing; I defer to the jerky experts!
I don't have any jerky planned until after the 2014 Deer season. But I think I'll just play it by ear and see how it goes. Maybe with the James Jerky Dryer there will be enough air movement where tray rotation won't be necessary. Wouldn't that be awesome?
I will be doing eight 25lb batches of Snack Stix some time in March though. I'll update in the Sausage section afterward with results.