I am on my 2nd pair of Alaska GTXs (I think that is what they are called) from Lathrop and Sons. These boots wear like iron and have lots of support, especially in steep rocky side hills. I have really big, flat feet and found that I had to order 1 size larger than normal. The company is really good to deal with and I would give them a call. I did not get the $150 extra size kit. I think you can just send them a tracing of your feet? I tried their new foot beds, but have gone back to green super feet.
Hope this helps.