(Ithaca, NY, USA)
I was looking to make a skewer kite today but ended up stumbling upon your paper sled design which didn't require a run to the store to get skewers!
The paper sled kite came together so easily and I took it out mid-afternoon hopeful that there would be enough wind to see it in action. I got it up a couple of times when periodic puffs of wind would come through and I was pleased at its performance. It went up and didn't wobble and stayed up long enough to get a "I like your kite!" and "It's made of paper?!" from a passing boy.
Later the wind picked up a bit and I took it to a big hill that I thought would make the most of the wind there was. The paper sled was a joy to fly and I got it up quite high several times.
The height I got made me glad I used the polyester thread as the flying line because I let a lot out and it still flew. By the end of the session the wind was getting a bit too strong and the kite would fly back and forth and eventually invert and spiral out of control. But it was fun to see how far I could get it before that happened!