I'm glad I don't have a clue about a caliber I've owned for 12+ years.....
Yes, the STW IS dumbed down in the loading manuals. Look at the loads offered for it. 3,000 fps for a 168gr bullet? Are you joking? No, that's not dumbed down at all... I'm pushing 3,115 fps out of a plain-jane 26" 7mm RemMag that I use for hunting... The STW should be able to easily do over 3,200 fps with a 168gr bullet. I should be able to get close to, if not, 3,100 fps MV with a 180 out of my STW.
So you're telling me that your 7mm Wby can't fit 70gr of powder in it? Because I know that's bullcrap. I have fit over 70gr H1000 in my standard 7mm RemMags. And fit over 74gr of H1000 in my .257 Wby Mag, which has the same case dimensions as the 7mm Wby, just with a smaller diamter neck.
Now, since we've established that the amount of powder I'm using for my 7mm STW loads to push 180's at 3,000 fps (71gr of 7828 SSC), WILL in fact fit in your 7mm Wby, Why don't you compare apples to apples... And please explain to me how it does this with that "10 more grains of powder" you were talking about...
As for that 2 more inches of barrel......Can't help you, as I won't own a magnum caliber without atleast a 26" barrel on it. And I **** sure ain't fixing to saw off 2" of one of my perfectly good barrels just to prove a point to some random person on the internet.