Grinding It Out

One allowance here buys 17,120 EXP, which places it 2nd of the 6 Lv 20 Carpenter tradecraft leves that record EXP. The best of them, Militia on My Mind, returns 28,010 EXP for the same allowance, 64% more.

Across that rung the return runs from 8,570 EXP to 28,010 EXP per allowance — 6 distinct figures spanning 227%, so the wrong pick leaves 19,440 EXP of the allowance unspent.

On whether to wait: the best Lv 25 Carpenter tradecraft leve returns 47,200 EXP per allowance, 69% more than the best on this rung, while the Lv 15 rung behind tops out at 24,790 EXP.

At Lv 20 this data holds 52 leves paying EXP across 2 categories: the 48 Tradecraft ones average 17,352 EXP per allowance, the 4 Fieldcraft ones 113,304 EXP, which puts this leve 1% below its own category's average.

Mudstone Grinding Wheel ×1 is a Lv 22 Carpenter recipe, 2 steps deep through 2 intermediates, costing 7 units of raw material and 5 crystals.

Handing that in returns 2,446 EXP and 42 gil for every unit of raw material the order swallows, and the tree needs Blacksmith and Carpenter.