So post 2 positions. If Z is worth 50% more to you, then it's clearly a different position, even if the responsibilities are a superset of the lower position. Most companies have levels for exactly this reason.
It's not hard to post 2 positions, and it prevents issues like many people have been bringing up with candidates having the wrong expectations.
It's not hard to post 2 positions, and it prevents issues like many people have been bringing up with candidates having the wrong expectations.