As previously stated you need to use a water base dye like Transtint or aniline dye to color S&G panels. Once epoxy touches the wood you cannot dye it so the dyeing must be done prior to gluing seams. Also end cut wood fibers dye darker so it is best to dye prior to cutting and drilling the panels. So dye the panels before trimming. Tool marks will show on the dyed wood and cannot be sanded out without removing the dye and the dye cannot be touched up without showing. So put a seal coat of epoxy on the dyed wood prior to cutting the panels. Sanding through the epoxy will remove the dye so chines and shears will need to be left sharp.