As for Gold Chests and Green Chests, your Drop rate will increase the rate you find them. I have all ten items with [+20 drop chance], and sometimes I use luck potion. That means I have +200 drop chance. I only fight the last 3 screens to try to kill monsters lvl >31 since they drop the strongest weapons and armor,
I only got lucky once with this character, I got lvl 31+ boots, but I have gotten the 2nd strongest weapon and all armors.
Side note: I got a gold +3 shield (2nd strongest) with +1 block, it had a block rate of 26% I think? at lvl 4 block, I the shield blocks 35%.
Golden Armor is super high (>130 defense base) but I get more def from +x% Def and +x Def.