Consider 'r' as the handle length and 's' the resulting arc, or movement produced as a result of a given handle movement. As you can see in this image, with the same amount of movement (or angle you change the position of 'r', your handle), with a short handle, or short 'r1', the movement produced is the small arc 's1'. But, with the longer handle, or 'r2', you end up with a longer arc 's2'.
Since the kite experiences the inputs from the ends of the handle, it is experiencing the resulting 's' of a handle movement. Longer handles results in a greater input to the kite from a given movement of the handle. It essentially exaggerates any motion you make. Conversely, shorter handles result in less input to the kite.
As long as the winds are decent, Magnuson Park has several large, open grass fields that are excellent for open flying, as well as a few baseball fields that are nice. There are also a couple of turf fields, but I have yet to devise a way to anchor the kite on turf without using a stake. Kite hill has been quite crowded with people out on picnics and lounging around on the hill, not the ideal place to fly.
I also came across a nice field at the Beacon Hill Skatepark (beside the golf course). It looks as though few people know about it because I have yet to see anyone else there except a couple of kids playing frisbee.
I'll definitely check out Chambers Bay when I get the chance to drive down.