I'd start with the eastmans MRS section. They give you a good breakdown of the better units. Also use the DOW website, there is tons of info. on there from maps to statistics on each unit. Pick a few units, then start to explore them with the maps on the DOW website and Google Earth. Then once you narrow down your units call the DOW and ask them specific questions about areas you have researched. It's a process, but the more you can learn on your own, the better off you are of asking the right questions to get some good answers. Then...the most important part is to scout, hunt your areas you pick and learn them. It's going to take a lot of time and luck to find a "great" OTC unit, Im yet to do it. But you can only keep trying and researching. Mike Eastman has a good book on elk hunting and picking areas that will inhabit elk also. So far in my elk hunting experience it's not so much finding the perfect unit, it's just knowing the unit you are in as good as you can.