For me, there's no cap. No amount will be where I say, "This is enough." So I come at the topic from the opposite direction and keep tabs on how long what I have would last us, assuming decent conditions.
A very quick and dirty estimate of how long your canned supplies could sustain your group could be done by counting one quart jar or one 15-oz can as a day's supply for one person. Yes, that person is going to spend half the day feeling less than full, but will not starve. Some people count double, some half. You can do the math or let the differences cancel one another out--this is the power of averaging. This method lets you know where you stand right now, and lets you update with very little effort anytime you want. I'm looking at a shelf with thirty cans of wet food, 15.5 to 19 oz apiece; for the three of us, that's ten days in which we would not go hungry.
Boxes and bags attract bugs. Sugar sucks humidity out of the air and becomes a brick. I have become a fan of airtight containerizing.
Two-liter bottles are working very well for me right now. Being able to see food, in variety and in quantity, comforts me; at the same time, being able to see what's there encourages rotation. (Yes, I know some items do last longer if light as well as air is blocked.) I see a two-liter bottle of barley or soup beans as five person-days of food, or more accurately I see three bottles as fifteen major meals. I rotate the newer bottles through my home office first. When I'm feeling fidgety and anxious, I count them and do the math, and sometimes can then turn back to focus on my work.
Someone at the office is now using Poland Water in the three-liter bottles, which stack vertically. I am looking forward to testing how stable and sturdy these bottles are.