Where I grew up and learned to sail, people didn't use spinnakers. They were considered gaudy and dangerous: wing-and-wing was good enuf for granddad, by God, it's good enuf for you whippersnappers.
Upshot: I never flew a kite. *cringe* We recently took our SJ21 to Fremont Lake and had a few days to muck about. We brought along the spi from our Buccaneer 18 -- about 60% as big as the stock SJ21 chute -- and used it to learn with. Practised deploying, jibing, reaching, dousing, without the stress of doubling our working sail area. "Chicken chute" ain't a bad way to go when you are learning, although the larger J made it tricky to get the kite out front far enuf.
Probably looked ridiculous to other boats, but hey. When you're sailing a 1973 tub the color of a banana, you don't fret appearances. Up next: buying a full-sized kite for the SJ (used, crummy) and learning to sail the Bucc -- a boat already desperately unstable and overpowered -- with the spinnaker.