That's Some Fine Grinding

One allowance here buys 21,830 EXP, which places it 5th of the 6 Lv 25 Blacksmith tradecraft leves that record EXP — a figure 1 other leve on the rung matches exactly. The best of them, Lancers' Creed, returns 47,200 EXP for the same allowance, 116% more.

Across that rung the return runs from 21,830 EXP to 47,200 EXP per allowance — 4 distinct figures spanning 116%, so the wrong pick leaves 25,370 EXP of the allowance unspent.

On whether to wait: the best Lv 30 Blacksmith tradecraft leve returns 67,730 EXP per allowance, 43% more than the best on this rung, while the Lv 20 rung behind tops out at 21,600 EXP.

At Lv 25 this data holds 52 leves paying EXP across 2 categories: the 48 Tradecraft ones average 31,772 EXP per allowance, the 4 Fieldcraft ones 204,269 EXP, which puts this leve 31% below its own category's average.

Initiate's Mortar ×1 is a Lv 24 Blacksmith recipe, 2 steps deep through 2 intermediates, costing 9 units of raw material and 8 crystals.

Handing that in returns 2,426 EXP and 15 gil for every unit of raw material the order swallows, and the tree needs Blacksmith and Carpenter.

The record carries a repeats value of 2. This site reads that as 2 further turn-ins on the same leve — an assumption, because the source data defines no meaning for the field — which would put the ceiling at 65,490 EXP and 411 gil for the 1 allowance it costs, or 65,490 EXP per allowance.