Some great ideas evolving here.
I think having only a single bag slot, with a chance to increase to two as the character improves, is spot on.
I would go further, and not allow the larger weapons to be carried in bags at all since, in reality they couldn’t be.
Nothing to do with weight, as they weren’t particularly heavy anyway, just the size. Try fixing a weapon, that is almost as tall as you if not taller, to your body in any way that would be reasonably accessible in combat or even practical while travelling.
So brothers who want to wield the larger weapons, great-sword, billhook, spear would need to have them equipped from the outset. If they then wish to switch to something smaller in combat, then, abstractly they would stick those weapons in the ground or drop them, use the smaller item and then pick up the larger weapon afterwards.
