Wax or silicon makes an easy job of that .I use plugs if thier made but silicon and a little waxed paper around the inside and save a little resin . Put just a dab on the wax paper strips and fill up the hole . Quite a bit to fill in the holes i guess but it pops right out if you leave holes in the fiber . It may be less time consuming to cut the fiber after its set and a little green.