Best of luck with your health and your rifle build. Interesting how some of us geezers put so much importance on the reputation a cartridge has built for itself. Sounds like you have someone who can build a fine shooter, let us know how this all comes together.
Me, I will go with a 7mm WSM
someday despite the excellent reasoning that the guys provided. Probably have to get another NonTypical from George Gardner since they are about as nice handling a rifle as I have ever played with and I happen to have the first ever built. George tells me that the M-700 WSM actions work very well, feed real nice, he has worked on the Remington M-700 a time or two.
Have to scratch the 6.5 itch first tho.