Utah seems to have a certain tolerance for LDS Tory Dems, and Matheson will be very hard to take out, and if you try too hard, an LDS Tory Dem might knock off some incumbent Pubbie unexpectedly, or win an open seat if somebody vacates it. It has happened before - or nearly happened. So I would bear that in mind.
Whatever district you draw for Matheson, the other three districts are going to be R+20ish anyway. (You can't weaken them too much or else Matheson will just run in one of them). The increased safety at the margin from making them a few points more Republican is pretty inconsequential.
Furthermore, you have to weigh up the risk that Matheson retires in the next ten years and the district you drew for him gets won by one of these "Tory Dems" you refer to it. I think the chance of this is higher than one of the other three districts going Democratic.