Tomes Roam on the Range

One allowance here buys 473,220 EXP, which places it 2nd of the 3 Lv 54 Alchemist tradecraft leves that record EXP. The best of them, Adhesive of Antipathy, returns 647,060 EXP for the same allowance, 37% more.

Across that rung the return runs from 256,810 EXP to 647,060 EXP per allowance — 3 distinct figures spanning 152%, so the wrong pick leaves 390,250 EXP of the allowance unspent.

On whether to wait: the best Lv 56 Alchemist tradecraft leve returns 534,960 EXP per allowance, 17% less than the best on this rung, while the Lv 52 rung behind tops out at 480,670 EXP.

At Lv 54 this data holds 54 leves paying EXP across 3 categories: the 24 Tradecraft ones average 400,590 EXP per allowance, the 3 Fieldcraft ones 938,680 EXP and the 27 Grand Company ones 205,186 EXP, which puts this leve 18% above its own category's average.

Gil ranks it differently: 936 gil per allowance is 1st of 3 on the same rung against 2nd on EXP, with the best there paying 936 gil.

Dhalmelskin Codex ×1 is a Lv 55 Alchemist recipe, 2 steps deep through 4 intermediates, costing 22 units of raw material and 29 crystals.

Handing that in returns 21,510 EXP and 43 gil for every unit of raw material the order swallows, and the tree needs Alchemist, Goldsmith and Leatherworker.