It's all going to boil down to how much recoil you can handle without developing bad shooting habits. Heavy recoil can cause a shooter to start anticipating it and flinch at the shot.

Winchester is no different than any other marketer. They are going to make their product sound like the best it is. Truth be known, even though the caliber is named for the company that introduced it, it doesn't mean their ammo will shoot best in a particular gun.

A 6+ lb rifle is light and even if you add accessories like scope, bipod, etc, you're not going to eliminate recoil. It's a fact that the more weight there is, the less you feel the recoil. If recoil concerns you, I wouldn't get the T-3 Light in anything but a .243, 7mm-08, etc. Even the standard .270 may kick more than you want in that light of a rifle. But then again, it's all in how YOU perceive the recoil. If you're a youngster (I say this in general because I don't know you) and you weigh less than 150 lbs, then I'd say that the .270 wsm is going to bother you in that light of a rifle. However, if you are experienced, and weigh more than that, it may not bother you at all.

From personal experience, out of a standard 7 1/2 lb rifle (naked), the .270 / 30-06 was about all I wanted to shoot. I did try a .300 Win Mag in a rifle in that weight range and while I didn't notice it in the field, I didn't like it at the bench. I shoot alot, so I got rid of that rifle. I developed a flinch that took a bunch of .22 shooting to get rid of.