I hunted 16D and got around just fine in a pair of wolverine hunting boots 2 years ago. I went to colorado last year and now am wearing Meindel Perfekt 10's, one scouting trip in the real mountains shredded my feet. That said I think the gila, while it can be rugged, is nothing like the northern rockies, any decent off the shelf hunting boot should work for you, just make sure you break them in before you go and wear thick socks, regardless of the temperature.