As Mark says one pin will do it if the thimble is
well inlet. That means it fits in its inlet with no rocking. When you go to drill the hole in the thimble tab
very gently clamp the thimble in place before doing so. Doing this will ensure the thimble is held snugly against the wood, and there is a bit of tension between the wood, thimble, and wire pin. Also, having been there I can say that doing two pins does not ensure the thimble won't wiggle or rock, it is all about that inlet.
Good luck.
dave