Leeches are best, hands down. You actually only need 348 gathering for these. Without the FC buff, you are required to get at least two pieces of the Forager's set if you skip the Forager's rod - the vest and wristguards. With just those two, and everything fully melded (with i70 right side), you can meet the 348 requirements. The FC buff makes it even easier. Here's one set of gear that works. Note you can use HQ Trapper's Quiche instead of HQ Tomato Pie - either work. There's no need to waste Spinach Quiche on this fish.

As a note, without the two Forager's pieces, HQ Spinach Quiche doesn't get you high enough. Even with just the vest, HQ Spinach Quiche only gets you to 347, one too low. However, with the FC buff, you can forego the Forager's gear and use HQ Spinach Quiche to just barely get enough to get you there.

And yeah - RNG is king with this fish. Having a little more gathering won't help. The worst with this fish is when you catch an HQ one. You need 3 fish for the quest, and they all have to be the same quality. 3 NQ or 3 HQ. If you catch 2 NQ and 2 HQ, you're SoL and need to get a fifth.