RE: Planned Caribou Hunt this September
I just wanted to reccomend a boot such as LaCrosse Alpha Burly.
They are a knee high rubber boot, if you didn't know. Mine were uninsulated.
Gortex type boots may get heavy if they get wet and they take quite a while to dry.
The Lacrosse type boots are light weight and comfortable. They remind me of wearing bedroom slippers.
I went on a moose hunt in Newfoundland a few years ago. We went the first week of October. I'd imagine your temperatures would be similar if not slightly warmer. The uninsulated boots performed well, although we were always walking.
One of the guys on my moose hunt also went caribou hunting a few years earlier with the same outfit you are. He had a great time. I think you will too.
Good Luck!