It depends on your age, steadiness, etc. as to whether you would have a problem with 15X steadiness or not. What might be okay for us may not be okay for you.

What distances are you hunting at home and what are you expecting "out west?" Are you planning on using a guide (he might carry a spotting scope, etc.) or going DIY? If the distances are going to short range on one and long range on the other, you may decide that 2 different binos are needed.

I have an old pair of Swaro 7x30's that are perfect for brush, forests and under 300 yards in mainly stalk and spot hunting (lot of hiking, spot the animal and stalk). If I was hunting longer distances with the same kind of hunting method, I would consider 8, 8.5 or 10x40 or so.

If I was hunting from a stand or spending lots of stationary time (not so much walking) spotting at longer distances (over 300 yards), I would look at more power, since 15x binos are much easier to spot with than a spotting scope and weight/size doesn't make much difference as opposed to when you're hiking a lot.

Somebody suggested trying out different power binos while reading road signs and that's a terrific idea. If you can't read the street sign name, you won't enjoy scouting with that power of binos.

You been given a lot of good advice but your eyes, hands and hunting style are what should determine which bino at what power is best for you. Good luck and let us know what you decide.