I have heard (but haven't seen) that there was an article in one of the single-shot magazines (either Single Shot Exchange, or Single Shot Rifle Journal) on how to reinforce that hole - and they did it with a piece of thin-walled aluminum tubing. If anyone knows about this article can you please let us know which magazine it was in, and when?
Also, regarding that early-version thin stock - I have one in 40/65 and it's still fine. I heard that the problem cropped up mostly when people put that rifle into one of those "stock-rest" type of contraptions for holding the gun steady while cleaning it or working on it. I guess some of them are designed to grip the stock near the belly of the buttstock, and if you're too aggressive with the clamp, you can crack those stocks.
The Lyman Snover bullet works great, but for black powder shooting, it doesn't carry enough lube! If you will be shooting where it is not too hot, or if it is hot, the humidity is high, you probably won't have a problem. But if you shoot where it gets hot AND dry you will have fouling problems. Here in Montana we will often be shooting in 90-105 degrees, with NO shade and humidity at 20% or less! That is very bad news for fouling, and with the small amount of lube this bullet carries, that just makes it worse.
Dr. Richard Gunn designed the Lyman Postell, but Lyman took the design and 1) made the lube grooves shallower, and 2) switched the ogive from a secant, to a tangent shape. NEI makes this same mould just as Dr. Gunn designed it (the number is either the 212G or the 215D - if you're interested I can find out when I get home), and it carries more lube. NEI moulds are sort-of "semi-custom" when it comes to price (about $100). I shoot the NEI 216A and love it!
When you clean the rifle, make yourself a little caddy out of wood and just set the rifle in it upside down and clean it that way. Any cleaning solution or black powder sludge then drips down out of the action. About every 1000 rounds of black powder, thoroughly spray the action with brake cleaner, and then after it dries, with G-96 Gun Treatment. My Browning has nearly 7,000 black powder rounds through it, and I've never had to take the action apart (and probably never will).