I would also suggest the one you shoot the best, and know the most about. Trajectory could be an issue with the .06 after a couple hundred yards, but if you are familiar with how it shoots then go for it.
Last week I killed this Roosevelt with my .270 shooting 130 grn Power Points. I had the option of a STW in 7mm and a 300 Win Short Mag, but I have used the .270 for more then a dozen years and I know it inside and out.
A perk of majoring in wildlife biology in college is the plethora of hunting knowledge that you collect throughout your course load. One of the most important factors in whether an area can hold large quantities of animals or produce large antlers is forage.
Most universities, state schools and even community colleges offer basic botany courses and plant ID courses. Although it might not be feasable for the average middle age hunter to pay tuition and go back to college to learn hunting...