Relating to endgame gear grind, this was posted on Reddit recently:
https://docs.google.com/spreadsheet...ZnZmYkJJejlvY3d1c25ucVdQYXc&usp=sharing#gid=0
It covers the cost of buying Darklight vs buying Tomestone items to have crafted into 2-star armor. While the majority of armor is more expensive crafted, there are a couple exceptions in tank chest/head and leg/feet combos pieces, and the healer/mage robes that are actually cheaper. In addition crafted 2-star with appropriate materia is usually better than Darklight, and tomestone items can be bought from other players.
It's not going to work for everyone, since you need to find a crafter with a very good chance of making the item HQ (as the NQ is near-useless), and tomestone items are very expensive (40-50k right now) but it is an alternate route to CM grinding. On my Warrior I avoided a lot of the grind by crafting both the tank combo pieces, though this was back when tomestone items were around 10k each.