I have quite a bit of experience with the Whelen, and recommend it for all the reasons listed by other posters who have responded. You can always cut the barrel down 2 inches if desired, as neither round are really maximum velocity long range numbers. Big bullets at moderate velocities is the name of the game.
While I have never owned a .350 mag., I have heard several issues from those that do. When used in a short action rifle, bullets have to be seated deeply, infringing on powder space. Since ultra light weight is not an issue, It would seem a long action rifle chambered for the 350 would be the way to go, allowing you to seat long bullets ( Barnes X comes to mind) out some, freeing up powder space.
Larry