No, the volume of the bag does not change. The only feature of the pack that can change between different sizes is the yoke and the waist belt.
We recommend sizing down if you are between sizes. It is very important that the waist belt is able to securely tighten around your hips. If your waist belt is too big you will have a hard time getting the weight in your pack to transfer from your shoulders to your hips.
Yes, the size range that we list on our size chart is not the minimum or maximum adjustment for the yoke and waist belt. There is a little extra adjustment available to accommodate additional layers.
Yes, please give customer service a call to inquire about our custom size program at 1.833.548.1999