We hunted with NAT in 2005 and had a pretty good hunt. At that time, the owner and his brother were splitting up the business and parting ways. Matt Owen and his wife (I don't remember her name) run the business now. It seemed that Matt has a ton of flying experience and knows his stuff but communication was not good and we talked to some guys that did a guided hunt with them that went south. Matt doesn't do any guiding but offers guided hunts, has subguides. We did an outfitted camp where the tents, cots, camping gear, cooking gear, etc. are all set up when they drop you. We didn't see any caribou until the 4th day when we called Matt to see what the heck was going on and he said a large bunch was migrating our way and it was so, the next morning we awoke to a mass migration of animals all around us. At that time, we just told him we wanted to stay a couple more days to tag out, we all shot two.
We had a horrible time with a taxidermist that worked seasonally for NAT. He was at their hanger in Kotz and guided hunters for NAT. He promised us the moon on our taxidermy work so we left our capes and antlers with him. This proved to be a very bad choice, he completely blew us off, it took years to get our stuff back, terrible job, etc. I had a unique cape that was just beautiful but of course didn't get my cape on my mount. We called NAT several times and they couldn't care less.
Like I said, we had a pretty good hunt but some things were left to be desired. After our hunt, their prices have gone up, you can only shoot one bull, sounds like they charge you for more days, etc. I would do your homework, and sounds like you are. I would like to do this hunt again someday so would like to hear about how it went and from others that know other outfitters in Kotz.