Anything the shoulder can handle, reinforced epoxy is plenty strong enough to handle out there where it all starts. From the standpoint of doing things right threading the hole and then coating it with Marine-Tex, a stiff epoxy compound, and driving them together is a little goofy.
Epoxy will form a perfect match with the threads, stick very well need nothing else. The threads if cut anything like the all-thread will wipe the Marine-Tex off on the way in.
And getting back to the definition of cross-bolts a piece or two of all-thread epoxied into a stock and hidden is not a cross-bolt.
