Weight/Item Limit

For the first run of keeping this as simple to follow as possible, think of your character's limit in the terms of a video game's inventory and equip area. You have a head gear equipment area, a chest/torso piece, shoulders, hands/forearms, legs/lower body, and boots/shoes. Then you have accessories - rings, necklaces, and the like. Your weapon is either in hand or sheathed at your hip or back. Magic is typically channeled though a staff or other empowered conduit until it's been mastered well enough to go through the character's hands or finger tips.

If you'd like to carry more than that, you'll have to buy packs or make temporary ones. Packs will be small, medium, and large in size with more to be developed. Small packs can hold 2 extra items of medium size or 4 extra items of small size. A medium pack can hold 2 large size items, 4 medium size items, or 6 small sized items. For a large pack, it can hold 4 large sized items, 6 medium sized items, or 8 small sized items.

In short, so you can mix sizes if you'd like:
A small item is 1 in quantity.
A medium items is 2 in quantity.
A large item is 4 in quantity.