several viable options for a smaller kit- sling pack as you mention, small lumbar pack, small daypack- you could even setup a light load bearing belt kit; also look at the water bottle holder thread- maybe this would be a viable carry option
water, clothing, food typically is what dictates the volume needed, the "hard" items themselves usually don't take up a lot of room
again there is distinctive difference in a minimal kit to make it through an unexpected night vs one that is designed to sustain for you for 3-4 days
I think the most important decision is to figure out exactly what you want this kit to do, from there you can refine your load-out and then based on the load-out you can determine the best way to carry it
water, clothing, food typically is what dictates the volume needed, the "hard" items themselves usually don't take up a lot of room
again there is distinctive difference in a minimal kit to make it through an unexpected night vs one that is designed to sustain for you for 3-4 days
I think the most important decision is to figure out exactly what you want this kit to do, from there you can refine your load-out and then based on the load-out you can determine the best way to carry it