Come on Gentry this is easy. It's a meat hunt, Take the cow at the end of the prime grazing season in the area you intend on hunting. She will have the maximum amount of fat and be in the best condition for harvest. If you are able to pick and choose take one that just 2 or 3 years old, At that age they should have enough pounds on them to satisfy your needs. As much scouting time as you have(yes I'm jealous) you should be able to pick one out thats been in an area that has the best and sweetest graze. Well thats my thoughts anyway. Keep posting those photos, It keeps me going here while I am stuck at work.
~Jeff~