I have installed a 5" maple plank floor (rustic maple... streaks, knot holes of which some are missing, and mulitple colors) which came out nice. Looks great just plain. Back to the real world - it needs to be finished... I am sanding a filling knotholes at this point, some quite large (1-3"). I have heard of filling the holes with everything from Famo-wood to epoxy, sawdust mixed with glue... what to do? I am applying a stain sealer before the stain and poly. I would like to get the knotholes dark to where they don't stand out. What is the best product to purchase or fabricate to fill these large voids?