I don't know what Weatherby's twist is, but Remington's has been--for years now--1:9 1/4 twist. Most Remingtons I know of will shoot the 105 AMAX too... I think Hornady designed the bullet that way, so you wouldn't need a custom twist to stabilize it.
Reynolds... it is encouraging to me also that these guns will shoot the 105's, and I agree it is indicative of a pretty decent barrel, that it will stabilize that bullet and shoot it well. Of course such a long bullet tends to turn in better MOA results at 200 yards and beyond, potentially not being 100 percent stable at 100 yards.
And the 87 VMAX is a great long range bullet too... with a BC of .400, and potential velocity from the .243 Winchester of 3200 to 3300 fps (easily), it's a pretty flat shooting bullet.
Practical Long Range Rifle Courses...
Optimal Charge Weight handload consulting