I've hunted Cows deer (the proper pronunciation) in Mexico, there stage 4 rut just starts at the end of December, beginning of January. I imagine in Az, they are in stage 4 rut now. As such, given your selection, I would go for the 8x42s and the spotter on the hunt with me for both species. You just can't carry everything you want on a backpack hunt. I'm also 53, and still pack in on many of my hunts. This season I had the pleasure of carrying a 100 plus pound ( the scale topped out at 100#) backpack several miles to camp, and then several more to the awaiting ice chest. So I say, plan for success. This time of year, you need to be prepared for possible weather, let alone the cold we all know will be present, so your already looking at a pretty full pack for a hunt lasting more than a few days. I prefer my 82mm spotter, but your Razor you have will get the job done, and between the binoculars and spotter, you have everything covered. If your at all picky about the buck you take, you will want the glass to confirm the maturity of the bucks rack given the opportunity at distance.
Best of luck!