Polyester does not bond with or stick to epoxy. Epoxy will stick well to sanded polyester. ...and if there's blush, the situation worsens. If you spent all that time and work on the kayak, I would just buy a small amount from the local boaating store and do it right. Then you'll never have to worry about it. If you drill through it for grab loops you always have to worry about water getting in behind the polyester/epoxy joint.