My opinion, never ever, ever, ever, ever, ever, sail your swing keel C-22 with the keel in any position but in the full down position. The boat's righting design comes from the keel being all the way down, pull it up and you loose stability. Take a look at the C-22 spec's. There is a reason why the wing keel version keel is so heavy, because to get the same righting, the shorter keel needs to be a lot heavier. Plus, take an unexpected knock-down, and the keel will likely come up easier and over she goes. Another reason why the C-22 class racing rules specifically address this situation and the keels are required to be left in their full down position.
Don