You're building your second rifle and you're kicking yourself because you've made a few mistakes? When you consider the relative ease of assembling a T/C kit, and the seven-year space between then and now, for the most part you can pretty much consider that this is your first go at building. You're being waaaaaay too hard on yourself!
Your trigger pin issue can be fixed with a pin made from some of the wood you'll remove from your stock as you work it. If your pin hole isn't too large, a round toothpick will work well. Neither method will be totally invisible, but a misplaced, plugged pinhole doesn't constitute the end of the world. As for the other mistakes you allude to -- run them by us. Someone will know how to fix anything and everything you've done.
Lest I sound too all-knowing -- you asked about mistakes that others have made. Oh, let's see. I've run the ramrod drill out the bottom of the forestock and up through the web between the ramrod hole and the barrel channel. Each time, I was building from a blank, and was able to use wood sawn from the sides of the forestock to patch the long, ragged hole. In the one case where the splice didn't even come close to matching, I inletted a wear plate -- a long strip of sheet brass that protects the thin wood in that area and, in this case, hides damage done in the building process.
I've split away pieces of wood I didn't want to remove, using a chisel to gouge off the biggest chunks prior to rasping things to shape in the butt area. Stainable wood glue works wonders in cases like that.
I've destroyed more lock parts than I can even remember, let alone count, due to bad drilling, bad heat treating, bad filing.... Thankfully, the same people who sell locks and lock kits also, very thoughtfully, sell the various individual parts.
Once every few months or so, also, I violate the rule about keeping one's hands out of the way of where the blades will go, should one slip. Since I'm right-handed, my left hand has an impressive buildup of scar tissue on it, including a really neat, numb lump at the end of my ring finger, which is the huge chunk of the tip I almost completely severed when the wood I was attempting to remove gave way unexpectedly.
And, lest this all sound too hopeless -- like some people are just incapable of getting it right -- throughout all this I've learned to build a pretty decent rifle. These were, with the exception of the self-mutilation, for the most part early mistakes. I learned from them.
Feel any better now?
By the way, after you patch the crooked pinhole for your trigger -- you don't need to drill all the way through. There's enough wood between the trigger mortice and the outside of the stock to provide a solid base for the trigger pin, without punching all the way through. This eliminates the need to position your trigger in relation to the sideplate.
