I've hunted most of those units and for me it's a toss up 'tween 20 and 49. I know both units very well, both units hold nice bulls, both units have a lot of private land. But if I had to choose one unit other the other, I would spend my 8 pp's in unit 49. The deciding factors for 49 over 20 would be RMNP and less private land. The elk in 20, when pressured, will use the national park and private land as sanctuary very fast and they may not come back across in the limited time you have to hunt. Unit 49 has far more national forest land than unit 20.
