I just sanded the dried fillets, then fiberglassed over them. Not with tape, but while sheathing the intire inside.

The fillets in the hull were strong enough to hold the shape of the kayak, while I built a deck on top of it, and then glassed the outside of the hull. after all this I finally got around to glassing the inside of the hull, over the fillets.

however, I've yet to use the kayak, I'm confident it will be acceptable, but have not tested it yet.

Myrl