Enchants. I honestly wasn't 100% certain which enchants were best, since scaling has screwed up a lot of things. IMO, just pick the enchant for each armor slot that has the highest bonus without level restrictions. The exception is that you'll definitely want Mark of the Hidden Satyr for your neck piece, and probably Elemental Force for your weapon. Both of these proc consistently and strongly across all levels.
The power of items depends on their item level, which you can see on the item's tooltip; the higher the level, the better an item will be. However, the Warforging and Titanforging system - introduced in the Warlords of Draenor expansion - means that almost any item of Uncommon, Rare or Epic quality has a chance to ‘forge' to higher than its base item level: Warforging is up to +15, Titanforging is up to +45.
Instead, go to Timeless Isle and take the portal to Gorgrond. From there, fly to your respective faction starting zone(Frostfire Ridge or SMV), go to your garrison, and do the quests to unlock your garrison(A short quest chain beginning down near the water where you'd otherwise start after the Dark Portal scenario). For now DO NOT collect any more treasures than absolutely needed to buy 2 experience potions! Treasures continue to be worth superior exp/h all the way to level 104!!! You don't want to begin collecting them until lvl 100 or later.
For reference, my previous best time abusing Method-0 in 7.3.5 was 32.4 hours(as show in the old thread). A difference of just over 8 hours; which isn't all that bad, all things considered. And I believe I made several errors along the way, which could be cleaned up in future runs. I believe that that gap could be significantly closed by using a monk's bonus, but I hate playing monk...so...yeah. YMMV