Hmmm. Okay I take your point about nudging it downwards in an effort to align it near the vrock. Okay, so going with 2d8+6 gore, 2d10+6 and 1d8+6 tail.....?
I was thinking we could make the Gore 2d10 + 6 damage as well as the Stomp to honor the d10s used in the original's two attacks.
Once the Paralysis is factored in I suspect it'll come out to higher than CR 7 but we can cross that hurdle when we come to it.
Shall I update with 2d10+6 gore, 2d10+6 and 1d8+6 tail?
The trunk is a bit of a special case, as the original was a "pick up and toss" attack that did unspecified (but doubled) falling damage.
So I'm thinking that if it hits an opponent of Large size or smaller it tries to scoop them up and hurl them, but if it's larger than that it can only try to trip them up. I'm thinking we might allow the target to use either DEX or STR on their saving throw, whichever is best for them.
I'd have it do a bit more than 1d6 falling damage though. Maybe 2d6 as the original did "double" a normal fall? That matches a 20 foot vertical fall, suggesting it can hurl a creature further away than the 3d6 feet we've got listed. Maybe make it 4d6+6 feet for an average of 20?