This is just an update for those who might be interested. I ended up purchasing an Ocean Venus sit-on-top kayak. It is in addition to the inflatable dinghy that I store in the starboard cockpit locker. The kayak is secured on the port side deck by lines bow and stern tied to the nearest stanchion base, and by a bicycle cable lock that is threaded through one of the kayak scuppers and then around my side stay. Under sail I move the kayak toward the stern, which seems to be the best position both for the kayak and to minimize possibility of interference with my roller furling line and jib sheets.
This stowage configuration works reasonably well even though it essentially prohibits use of the port side deck as a path forward. By mounting on the port side the starboard side remains unobstructed (essential for reefing). Stowage of the kayak itself is also facilitated by the way it seems to lie against the cabin top on one side and rest against the shrouds on the lower side.
Last weekend I was out in 25 knots apparent, motor sailing to windward at about 30 degrees apparent, and in pretty boisterous wind waves. I was pretty well soaked at the wheel, the foredeck was drenched with spray, and boat motion was pretty severe at times. The kayak seemed to move gently with the boat's motion but I did not see anything that really worried me. Later I eased off to a broad reach and as the wind dropped to 15 or so I unfurled the jib. We moved along at 6 to 7 knots in the same sea state and all seemed to remain secure.
My conclusion is that a single kayak stowed on the port deck can work reasonably well on Libations since my port cabin top is used for life raft stowage and I typically go forward on the starboard side. For a second kayak to work on the starboard side I would want to mount it as far forward as possible so that I had easy access to the cabin top and foredeck. The major problem with this stowage strategy would be obstructing the anchor well. I may still try a second kayak but this is what I can report thus far.
Any thoughts from others would still be appreciated.
Richard