As you can tell, I'm partial to the 358 Winchester, but love all the 35's. If your loading your own there really is no good reason to drive the 225 TSX faster than 2,600. Even at 2,600 it will bounce a very large bear and is pretty much overkill for everything else in the U.S.A. Take a look at the drop figures with a 200 yard zero the difference between 2,600 and 2,800 is just over an inch in drop at 300 yards. I think you can live with that. The bonus prize is that at 2,600 the recoil and the muzzle blast are A LOT more tolerable.
All pistol bullets for 380/9mm (.355), 38/357 (.357) will work handily in the .358 bore of your 35 Whelen. This allows you to use your rifle for more than big game. Load the pistol bullets down to about 1,800 fps and you have a fine small game load up to about 200 yards. Then if you ever go to coastal Alaska and want to get a really big bear then go ahead and load it up to full steam.