On my bowhunt lease, it is old school and inexact but there are a lot of hunters on there in all seasons. The owner has a rule that bucks need to be 8 points and wider than their ears. This is a good visual to reference but it sure doesn't go far enough to really let those young bucks with high potential walk. There are many weakness to this approach but it has helped a lot. There is no culling poor genetics. in fact you tend to take only those with good genetics! On a positive note, it does mean however that I see quite a lot of bucks that are in their 2.5 and 3.5 years and getting to be pretty nice, with the occasional buck that has eluded hunters that is a 5-7 yr old and will be a keeper.
So much depends on if you can trust he others on the lease to follow through with the concepts and they know how to judge a deers age. Also, you can try to only shoot 5 yr old or older deer on your 600 acres but they all get shot at 3 yr olds when they step onto the neighboring ranches. If you have 6000 acres, you can manage this much better.