The Aquariums of Ishgard

One allowance here buys 1,083,092 EXP, the best on the Lv 54 Fisher fieldcraft rung — matched exactly by 1 other leve of the 6 there, with the rest trailing at 649,855 EXP or less.

Across that rung the return runs from 108,309 EXP to 1,083,092 EXP per allowance — 4 distinct figures spanning 900%, so the wrong pick leaves 974,783 EXP of the allowance unspent.

On whether to wait: the best Lv 56 Fisher fieldcraft leve returns 1,191,215 EXP per allowance, 10% more than the best on this rung, while the Lv 52 rung behind tops out at 1,001,778 EXP.

At Lv 54 this data holds 54 leves paying EXP across 2 categories: the 6 Fieldcraft ones average 622,778 EXP per allowance, the 48 Tradecraft ones 296,533 EXP, which puts this leve 74% above its own category's average.

Nothing on the turn-in list is craftable in this data: Buoyant Oviform ×3 has no recipe here, so 3 units must come from gathering, a vendor or a drop.