hello john,
something to keep in mind is, how do you intned to paddle your craft? if your are going to use a double ended paddle or a traditional canoe paddle. if you use a kayak paddle it will drip onto your lap with every stroke. if this is the case i'd go with a spray skirt. i'm a first time builder just like you so my opinion may not weigh as heavily as mr leidy ( et. all) but i'd try to put some sort of lip on it. laughing loon makes spray skirts for their rec. boats that may fit your opening. something to look into. good luck.
brett the hitman hart.