Moleskin, I've often read comments like yours that indicate you'd rather come home with a tag than shoot a 300" bull. I'm disappointed to read that, as most guys in all honesty have never shot a 300" bull. Think about that for a moment, because it is true. There are many thousands of bull elk killed all across the west every year, and I'll bet that less than 5% of them score 300" or higher. Now that I've said that, yes, unit 31 is an excellent place to try to kill a bigger bull, but unless you've already killed several bulls bigger than 300", why would you pass up one that size? If you have, my comments may not apply to you, but if you haven't shot a few bigger than that, why would you pass up such a nice bull? I'll venture a guess that over 80% of hunters wouldn't know what a 350" bull actually looks like on the hoof. Most guys would be thrilled to have a legitimate shot at a 320-330" bull, and it'll likely be the biggest bull they ever shoot. There are lots of 310-330 bulls killed every year by guided hunters where the guide tells them 'congratulations, that's a solid 340, or 350, or 360 class bull, and the hunter never knows the difference or cares to verify the guides estimate. Why would he, he can only be in for a letdown if he has it measured and realizes that he shot a very nice bull, but not the exalted 350"er.
If you've taken bigger before, by all means be selective, have a great hunt and don't be afraid to come home with a tag in your pocket. If you haven't shot a few of those caliber of bulls, don't be so darned picky and get yourself some experience, still have a wonderful elk hunt and be damned glad to get an nice bull regardless of how big his antlers might be.
That's just my unsolicited .02, but it comes from someone who's done a lot of elk hunting, and taken a few really big bulls in addition to other smaller bulls.