Depends a bit on the base stats & your bve status.
From what I recall (not very active these days and its been a while since I lvl'd my qv crew) your focus should be on reload, because accuracy cap is easily reached and you can gain more from the extra reload.

I think I classed my main gunners 2x rel & 1 x acc, no clue in what order (not on my pc atm)

IF; you do not have any bve (or very lightly)  id recommend leaning more towards accuracy to optimise your spread a bit.

maybe is also not bad to use 2 sets gunner, 1 for low lvl classed as acc gunner and the other on t-slots classed as reload only. Later in high lvl if you reached the acc cap with the t-slot gunner you can switch and use the acc gunner as hedgehog gunner on your t-slots

Unless something has changed, RN doesn't have the option of changing back and forth between accuracy and reload.

Traditionally people would get a sailor with higher accuracy (elite accuracy or 12/10) and then classify it as a reload gunner.

Reload all the way and add vets to get the accuracy back up.
But as stated earlier. You can get Elite Acc gunners and then level them as reloads.
If you have the gunners already. Just make em reload and thats all you havea choice with.