Re: WSM/WSSM ?
If you are not married to your bolt, you can do ALOT better by replacing the WSM bolt with a .473 bolt and using a regular .243 or .243 AI or one of the MANY other 6mm choices. Plus good luck finding wssm brass in the future--if I am not mistaken, wssm was at best, a fad, and on its way out.
In addition, by moving away from the wssm, you will have better options if you ever want to mag feed.
If you really want to make the most of the WSM bolt, look at the 7wsm.
Good luck with your build no matter what you chose.