Boogershooter. I can't comment on the X bullets as I've never used then. The TSX bullets are the X bullets improved.
The TTSX is just the TSX with a plastic tip. I haven't used then because my LGS doesn't carry them but only the TSX.
As I mentioned earlier, I've only shot elk with the and while most had been broadside or slightly angled shots, on elk was hit just behind the short ribs and the bullet exited between the shoulder and the neck. The insides were a mess.
My son in law and I both have Winchester M70 Featherweights. His gives tight groups with the 100 gr. TSX but mine not quite so good. He thought his scope was off so we fastened a beer can found on the ground to a roughly 18" thick pine tree and he shot at 50 yards. The can never moved. He shot again, still the can did not move. He asked me to try and the can finally fell and had there hole close together. Checked the tree and all three bullets had passed clean through.
I'm also playing with a 140 gr. TSX in several rifles chambered to the 7x57 Mauser round but so far accuracy has not been all that good. From what research I've done, they can be fussy regarding seating depth so that's what I'm working with now. Then again, some rifles like them and some don't. You can only try them and let your gin tell you what is likes.
As far as using that 225 gr. TSX on the great bears? I wouldn't hesitate. I think they're that good in a .35 Whelen.
If those don't work, look at the 225 gr. Nosler Accubond or Partition. They'll work too.
Paul B.