My son-in-law and daughter built and stained a pine table. I told them I would fill several large cracks/holes (1/16" to 1/8"") in knot holes with epoxy, and spray on several coats of poly. After reading several articles I see that I should have filled and sanded the cracks/holes before staining. Sanding off the stain is not an option. Any suggestions to fill the holes? Can I fill now with epoxy (mixed with dark sawdust) and just try to get it level? The table is a rustic style, but not distressed.