i just got my hands on a pop up 28. i live back east here in PA and id have to say it will be exactly what i need here. that being said, i guide in montana and im not sure that it will be the answer for that. i run a metcalf currently. i also carry enough stuff for 2 people most times just in case a client forgets something(it happens). you and i may hunt competely differently. my "heavy" gear is puffy pants and puffy jacket that i will stand hunt in down into the teens. if i were to lug my fanatic series stuff into the woods, the 28 would be stretching i feel. however you could definitely use the overload shelf to stack clothing in, which i have done many times when i carry my smaller mule bag attached. im goin to be putting some miles this weekend on the new popup 28. i have 30 pounds in it right now so im excited to see how it carries! if you can explain your "system" a little bit more maybe i could get you a much better idea if it will fill your needs. i have photos of the bag if youd like to see them, just shoot me a message!
I'd have to say you'll have plenty of room then. Utilize the main bag for all your clothes and insulin and the water bottle side pocket takes care of that. The lid and front pocket are surprisingly bigger than they appear on pictures. I have a big flashlight, license bag. And dark energy charger in the top pocket with more room to go. Didnt even dip into the front pocket yet and I have what I would need for a day hunt with the possibility of packing a deer out