Island Rhyno, I am Reg, and have two pair of orthotics. I was posted from the Strats in Edmonton to Wainwright last June and when I cleared in, they made me a "You're new meat, da MO wants ta see ya." appointment. She (the MO) gave me a chit for Vibram soling my boots (done through QM), and told me to go to physio. The Physio types measured me for orthotics and ordered a pair. They came in, and I tried them in various types of footwear. The Cbt Boots were the worst fit, as the combat boot fleet make up for an "industrial" fit by compressing the top of the foot. Since size 71/2 - 8C tends to be a tight fit anyway across the top of the foot (where the upper meets the tongue), it was a problem. Did I mention these were almost new boots? So, I took them to QM, and they applied alcohol or some such to them ( I have used Spray Pam in the past), and put "Stretching Devices" in them for 24 hours. No probs. I wanted to avoid, as much as possible, changing sizes, as anything bigger has no C width, and that will create a whole new set of probs, especially if I end up on tour again, and my orthotics disappear.
Before, I could do a 13 km, run half of it, and still have feet that could do it again. The orthotics will change your foot/boot weld, and you will have to work the fit up on practice marches. Keep a supply of moleskin handy.
Once this stage was successful, I had them order a second identical set. They can be "refreshed" once a year, and replaced every two years.
Good luck, and Ruck-on!
Tom