I like the standard Rem magnum just fine. It will reach out as far as I please.
If I did build an STW, it would not be with a standard mag. length action and a double-punched tube. Without getting into too much detail about it, let's just say I would not be able to seat bullets out as far as I like, and you run the chance of ending up with a sloppy chamber that is tough on brass. I suppose you could go with a Wyatts mag. box to solve the mag. constriction/seating depth issues.
I read an article by Layne Simpson years ago on his beloved STWs. He said he felt that the poor man's STWs being produced by punching out 7mm RMs were turning out to be more accurate than the original factory chamberings. He said he was not sure if this was because of the more concentric chambers being cut by the gunsmiths or that the 7 STW was just a more inherently accurate cartridge than the 7mm RM. I got a good chuckle out of that, because not only do I disagree on both counts, old Layne has never missed an opportunity to toot his own horn. He is definitley a legend in his own mind. But not in anybody else's.
Anyhoo, reamer selection and smith selection are absolutely critical if yo go RM to STW. I'd be VERY particular as to both selections.
Oh yes, and I'd not fret the barrel stamp too much as it is easily hidden and restamped.
JMO......