I don't weigh my food because it's depressing, but if my week+ trips last the intended duration and I shoot something, and the packout is tough, I eat it all and lose ten pounds. I'm thinking 1200 calories a day would kill me.
The sub-6000ci pack phenomenon has me a bit baffled as well, for one-tripping a deer or sheep. One-trip of a sheep had my horns atop the fully extended drawstring-blouse-deal on the top of my terraframe, held down by the lid. Cape and ul drybag of clothes were strapped to the loops on the back. Pack was JAMMED. Maybe the Stone-Glacier sandwich style relieves some need for capacity.
Your Astralplane will be fine if you figure out a way to suspend your meat bags between your shoulder blades instead of letting it slump to the sleeping bag compartment baffle.
