I'd go with many head, cobalt and ardite plate + ardite rod. It should get about 10 bonus when almost fully worn out IIRC.
Also scythe can one shot skeletons. I made manuyllyn one with cactus rods and with a couple of quartz it was one shooting them at about 1/3 durability left, so jagged is definitely worth it, I'd go with cactus as a rod for every weapon.
It depends on difficulty, the harder you set it, the better armored enemies are. I don't think you will get any armor on easy.
Edit:
So apparently you can just use nbt editor to edit durability on your tools to test it quickly. Here is manuyllyn head, ardite rest hammer with silky:
http://imgur.com/qCjjjSF
No other modifiers applied, 21.5 mining speed.
Also scythe can one shot skeletons. I made manuyllyn one with cactus rods and with a couple of quartz it was one shooting them at about 1/3 durability left, so jagged is definitely worth it, I'd go with cactus as a rod for every weapon.
I guess you're right about the armoured mobs, but they're rare... Come to think of it, I can't even remember the last time I saw a zombie or skeleton wearing any armour.
It depends on difficulty, the harder you set it, the better armored enemies are. I don't think you will get any armor on easy.
Edit:
So apparently you can just use nbt editor to edit durability on your tools to test it quickly. Here is manuyllyn head, ardite rest hammer with silky:
http://imgur.com/qCjjjSF
No other modifiers applied, 21.5 mining speed.