Sure, fill the void with a hardwood dowel epoxied in place. No need to waste all that epoxy. And really, no need to use the relatively expensive Accraglas on a project like this. I mentioned having the stock on a Lefever G grade split due to a solid mass of oxidized lead shot. After I cleaned it all out and repaired the split with Titebond II, I used a walnut dowel I turned to fit on a lathe, epoxied in place to fill the void. Several years later, and the repair is still great.
By the way, larger volumes of mixed epoxy often heat-up and cure very rapidly, foaming out in the process. Another reason to not fill a large void with straight epoxy.
