Well Harry you're making me nervous since it sounds like a really important decision and also sounds like you may not be able to test paddle the various Swifts.
Do you kneel or sit? Do you want the hottest boat possible or some extra stability?
I've not paddled a Kee 14 but I've paddled my friend's Kee 15 and I've got an Osprey and a Shearwater. The Kee 15 is an efficient cruiser with surprising initial stability even for sitting paddlers. It reminds me of my Bell Merlin II but with even more stability. But neither boat is fun to play with on ponds...they are cruisers.
The Osprey is a riot on quiet water...one of my all time favorite boats to just play around in. It's a fine river boat....way better than either Kee. I think you can still order one. They have some personality (quirks) but most Osprey owners deeply love their boats. I kneel...if you don't kneel I might not recommend an Osprey.
Don't give up on the Prospector 14. You are within the minimum efficient weight range. Even though it is not as hot as the others you are looking at based on specs, it is a Yost design and you can see the rounded shoulders that should make it a sweet boat to play around in. I imagine it will give up some cruising efficiency to either Kee but at same time for your use it might be a good fit. I had an Oscoda Solo 13 that was a Yost design with little or zero rocker and it was a surprisingly sweet and fun boat on gentle water and I would imagine the Prospector 14 to be better.
At least I can state with confidence that the Shearwater is a bit too big for you.
