En Garde and on Guard

One allowance here buys 359,460 EXP, which places it 3rd of the 3 Lv 64 Armorer tradecraft leves that record EXP. The best of them, Greaving, returns 709,140 EXP for the same allowance, 97% more.

Across that rung the return runs from 359,460 EXP to 709,140 EXP per allowance — 3 distinct figures spanning 97%, so the wrong pick leaves 349,680 EXP of the allowance unspent.

On whether to wait: the best Lv 66 Armorer tradecraft leve returns 969,450 EXP per allowance, 37% more than the best on this rung, while the Lv 62 rung behind tops out at 595,710 EXP.

At Lv 64 this data holds 27 leves paying EXP across 2 categories: the 24 Tradecraft ones average 435,661 EXP per allowance, the 3 Fieldcraft ones 1,139,405 EXP, which puts this leve 17% below its own category's average.

Doman Iron Gauntlets of Fending ×1 is a Lv 64 Armorer recipe, 3 steps deep through 5 intermediates, costing 29 units of raw material and 29 crystals.

Handing that in returns 12,395 EXP and 37 gil for every unit of raw material the order swallows, and the tree needs Alchemist, Armorer, Blacksmith, Goldsmith and Leatherworker.

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 1,078,380 EXP and 3,246 gil for the 1 allowance it costs, or 1,078,380 EXP per allowance.