re: Filling small knots and voids

+1 with black starbond.....I use it on bowl voids works great...I use accelerator most of the time, altho I am not a huge accelerator fan for gluing non wood things and such.....I have used a lot of epoxy colored...I really do think it may work better than starbond for flat surfaces like yours, but a lot of messing around and you must purchase the color to mix with the epoxy and you must wait over night and usually involves a fair amount of sanding.  So all in all the starbond is easier and very close in results....