Re: brass and pressure question?
What powder are you running? That 20F can make a huge difference, especially if your loaded rounds have some time to sit in the sun.
My personal approach would be to back off the load regardless of brass used. You are seeing slight pressure signs in the Wby brass, so any number of factors could create an issue (new lot powder, different primer, bullet seated long, temperature, etc). I like velocity but view it relative to repeatability, safety, and brass life. With the velocities you are running, my opinion is that there are diminishing returns for running at the very high-end of pressure. Basically, the benefits of the extra velocity (at that weight/velocity, basically extra energy waaaaaaaay out there) are outweighed by potential issues (blowing out primers, a major oh-crap, breaking something in the field, etc).
Good luck an be safe!