I've been happy with Mystery Ranch, so I don't speak from experience specifically with the exo, however the sizes are all similar, and I can speak to that, since that's really what this is about.
Packs are just bags that carry your stuff. While there are special features in hunting specific packs, like meat hauling, they're still just bags for your stuff.
Since you know how you hunt, if you're saying it's too large, then it's probably too large.
Now, I wouldn't agree with that based off how I hunt. Because I hunt very remote western areas, even on a day hunt, I tend to climb excessive elevation, go through various forms of weather so I carry my layers, optics other than binos, as well as two meals because I'm out from before sunrise and usually I am walking back in the dark. Of course, I carry all the other stuff like kill kit, flash light, water filter and water container/s, etc.
So, for me, I tend to go no less than a 3800 pack. My typical hunts are bivy hunts, and that pack (Marshal) is like a 6200. That keeps me in the field for 5 to maybe 7 days.
