Subwoofer Vicash

Yeah it doesn't matter what size you make the holes inside the bracing. Just make sure the holes are large enough to allow decent airflow, but not so large as to weaken the brace. Use what vikash did as a guide.

Usually speaking subs do not require glass wool, or similar, at least not for the same reason that normal loudspeakers do. The only reason why you would want to stuff is to increase the apparent volume of the enclosure. This is tricky with the vikash build as it has passive radiators. You must keep the area around the passive radiators clear. As the box is so small it would seem pointless to really add much, if any, in.