The long answer is, it depends. You are not just treating purely pronation by itself in most cases. The foot can be pronated at the mid, rear foot or both and multiple causes are possible for the pronation. Knee, hip, and 1st toe positions play a role. Professionally I would suggest you see someone who knows the lower body biomechanics well and discuss the situation with them. It should save you both time and money if you have the right practitioner. Now that being said, if you want to play Google doctor I will give you some tips. There are two approaches to orthotics in the foot. You can either make a mechanical change or accommodate the foot. If you have “flat feet” and have ever tried an orthotic that caused increased pain then you probably have experienced a mechanical corrective based orthotic that was either too much correction, poor break in procedure, improper size based on foot dimensions with an OTC, or simply your foot does not tolerate it. I would start by going and trying on boots. I tend to see more people with a wider foot when pronated vs a supinated position and the ability to try on boots with different sock combinations that work for you will to be to your benefit. I can’t speak highly enough of picking a quality boot company. I have used Crispi, Lowa, Zamberlan, Schnees and there are many other good companies, but you get what you pay for. Bad boots can ruin your trip. Most companies have accommodating orthotics in them. See how your foot likes it after using them for a bit. No problems then great, you have your answer. If you are still having arch pain then orthotics would be the next step. These can get expensive. I have sent out orthotics to be made in the same process that Sheep feet offer. I don’t have any personal experience with their company and some will say it’s very expensive. Well if you go and mess around buying different OTC orthotics from a machine you stepped on at a store at 50-60$ a piece then you could have spent that towards a set of custom orthotics.