Leather or Chainmail Armor. Weight 1, Armor 1
Scale Armor. Weight 3, Armor 2. Clumsy.
Plate Armor. Weight 4, Armor 3. Clumsy.
Shield. Weight 1, Armor +1.Dungeon World
In Dungeons and Dragons originally, chain weighed twice as much as leather, and provided better armor. Plate mail weighed three times as much as leather, and was as much better than chain as chain was than leather.
The obvious move is to make chainmail Weight 2. But if we don’t bump up the Armor to 2, there’s no reason for someone to wear it instead of leather. But if we do bump up the Armor to 2, there’s no reason to wear Scale.
Easiest thing is to replace scale with chainmail.
Smartest thing is to make chainmail Weight 3 (Armor 2, 50 Coins); plate mail Weight 4 (Armor 3, Clumsy), and scale armor Weight 2 (Armor 3, Clumsy).
And to apply a -1 penalty ongoing to Druids, Thieves, and Wizards for wearing metal armor (in addition to Clumsy, where it applies), unless they have an Advanced Move to counteract the penalty. I’ll likely call this move “Elven Maile”.
Also, setting-wise for Lyonesse:
Leather = reinforced leather, such as studded leather, brigantine, cuir-bouilli or lamellar.
Hides, soft leather, or padded armors like a gambeson cost like leather armor, weigh like leather armor, but do not give you a point of Armor. They do avoid giving a penalty to movement or spellcasting though, and probably give you a point of protection from environmental damage like weather, cold, and falling.
Chainmail is probably a maile hauberk (torso, arms, head, hips).
Scale is heavier pretty rigid cavalry type stuff that includes leg protection and a helm.
Plate is similar, except Plate is explicitly Plate Maile, which is to say Chainmail, plus helm, breastplate, and greaves (leg armor).