Jim,
I am not familiar with swing keels other than the one on my "mighty" Cal 21 (wished I'd come up with that one!). My keel is basically designed to be lowered and left there. It's not that difficult to
rig the hoisting tackle and raise it and I'd certainly do so for serious gunkholing but, it would be a pain to sail it regularly with that gear rigged, though some do. I'd probably be motoring with it raised or partially raised.
My point being that I think you'd want a keel that can be easily raised in all conditions and that you will probably find that you want to raise it only to the extent you need for shallow water. It will cut down on the amount of leeway you make substantially...and my boat can make some serious leeway with it raised! If the boat is capable of being sailed with the keel retracted completely more's the better. The Southerly does not have any type of stub keel, as is my boat, and I'd be curious as to how she sails with minimal keel lowered. I'm guessing that full keel up is intended for motoring only.
Thoughts?