Hello, we just custom-designed and had made a kitchen island with a 2" plus century barn beam top consisting of 4, 6 foot by 12" wide planks. It looks great but we need to fill the many natural crevices in the planks and also seal between the planks. Whats is the best product to use for both of these needs, please? Keep in mind, we want it to be more antiseptic, and also the holes in the boards would look best in black or dark brown, and between the boards would be best clear.