I am wondering if a simple yet effective compromise between bolts, that require a wrench and gaskets, and clips, that are external to the hull, would be bike-type skewers. These are used on bike tires, seat posts, and come in all sizes. Using a Valley style bulkhead set-up, they could be put in the bulkhead holes instead of bolts and nuts, tightened, and when the lever is closed for that last little push, they are really rock solid. At least on a bike. Hmmm.
I think, before changing out the bolts, I will see if 17 mm wing nuts will hold. They might just be hand-tight enough, especially if the wing is large enough to get a great purchase by hand. WOuld be ideal to at least have spares for those "oh-oh" moments when the wrench falls into the lake.