Perhaps you could start with only the normal hotbar, and by traveling a while with a filled inventory you could gain xp in a carrying/stowing/organization skill? you could also add stack boosts as an option (a % modifier would be the most compatible), ability to pool similar resources, unlocking multiple hotbars/bag slots, move speed, jump height, pick up range, and so forth. maybe the single row version is the default of your "waist pouch slot", and you can craft tool belts, utili-kilts, cargo aprons, and the like to get more rows you can toggle through. just some ideas that seem friendly with your other mod, the request, and the feel of this mod as is.