Have a look on the www.kayakfishingstuff.com
hobie forum at the jib set up I devised for my Adventure/AI using a Topper sailing dinghy jib .
Using my jib I lose roller reefing/furling of the main (when on the AI and when using my AI hull in 'kayak' mode - I have made an adapter for using the small sail on the AI hull's roller reefing base) and the sail is not really at its best going upwind due to the lack of luff tension caused by the mast bending (staying the mast would alleviate this) but I have now used the sail very successfully both on the AI mast and the standard mast.
It adds significantly to the downwind performance of the boats and significantly reduces the tendency of the AI to get stuck head to wind during a tack. It does carry a greater risk of a capsize when sailing as a kayak (i.e. not a trimaran) though ! Overall, the lack of instant furling is outweighed by the additional performance and I now always take the jib when out sailing (stored in the centre hatch) in case I find myself in the right conditions/point of sail.