I guess I’m under a different mentality than most on this question. If you are buying them specifically for a “high country mule deer hunt”, I would assume you are hiking in. I personally would be leaving the money/15s and their weight at home. I would be taking a good pair of 10x or 12x on a tripod and a good spotter. I feel like generally you will find what there is on a mountain with 10s or 12s and then zoom in on them with a spotter to figure out if they are a shooter or not. I find myself with 15s still pulling out the spotter to figure out if they are a shooter and don’t think the weight penalty is worth it.
But with that being said, if you are dead set on taking bigger glass, I would agree the 15s are a great option. Love my meopta meostsrs. But again, I don’t take them on backpacking hunts when I am already taking a spotter. I find it redundant and a waste. Coues deer though is a completely different story...