Nearly There
Location
Required Items
Rewards
What the allowance actually buys
One allowance here buys 2,028,020 EXP, the best of the 2 Lv 86 Alchemist tradecraft leves that record EXP: the runner-up manages 1,248,870 EXP, 38% less.
On whether to wait: the best Lv 88 Alchemist tradecraft leve returns 2,297,800 EXP per allowance, 13% more than the best on this rung, while the Lv 84 rung behind tops out at 1,746,150 EXP.
At Lv 86 this data holds 18 leves paying EXP across 2 categories: the 16 Tradecraft ones average 1,557,007 EXP per allowance, the 2 Fieldcraft ones 2,953,920 EXP, which puts this leve 30% above its own category's average.
Gil ranks it differently: 4,980 gil per allowance is 2nd of 2 on the same rung against 1st on EXP, with the best there paying 5,000 gil.
Kumbhiraskin Grimoire ×1 is a Lv 86 Alchemist recipe, 3 steps deep through 5 intermediates, costing 34 units of raw material and 72 crystals.
Handing that in returns 59,648 EXP and 146 gil for every unit of raw material the order swallows, and the tree needs Alchemist, Carpenter, Goldsmith and Leatherworker.