I recently bought a Lefever 12 as a twin to my 16, and like my 16, it had some big cracks that needed to be fixed before I could shoot it much. I know these are pretty standard repairs to all the pros that post here, but I just wanted to share the fun I had fixing the old girl. Thanks for humoring me:
Before filling the cracks with acraglas, I drilled two 5/8" deep holes in the middle of each lower tang up into the head of the stock and then used small #6 brass screws, cut at the shaft and slotted with a dremel tool so I could counter sink them with a screwdriver, and then filled in the holes with acraglas. I ended up with two dark blotches on each lower tang after sanding, so I painted over with oil paint, refinished, and now the repair is pretty much invisible, and very, very strong. I probably could have done the repair without the screws, but I didn't want to ever worry about it cracking again:
