Not sure what to tell you here dude, the lion scene in Utah is pretty bleak.
If you want to kill a mature tom in Utah you will need, lots of time, LOTS of money and a helluva lot of luck.
But as for which unit, not really sure. I can tell you a lot of units not to choose. LOL
Best of luck, should be fun and enjoy the ride!! There are a few left out there, but the glory days of Utah lion hunting are long gone.
Be persistant and put in the time and you'll be fine.