That sure seems like a very labor intensive way to mount that stock. Myself I'd have just changed the stock "tongue" angle, cut the excess off and added a butt pad to regain the length of pull myself. Just seems to me a better way to do it rather than go through all the welding, re-tempering and refinishing of the metal. Way easier to re-work the wood than the metal, especially sense the wood needed a re-work to start with. Plus you have the option of putting the gun back to original at a later date, if you wanted to without a pile of extra work . I'm not being a smart ass here ,,, so don't take me wrong, but not the method I'd have used.
I'm sure it will come out fine ,,,, but wow what a bunch of extra work!! You must be retired too and just want to experiment some,,,,,,LOL!!!!