Pretty sure its catch rate is the only reason why we have this pseudo-legendary in the game. Ame usually has us work for the prize.
Also nest balls are the best choice for it, with a 3.9x multiplier against a level 1 target to your great ball's 1.5x multiplier.
EDIT: Technically, Dusk balls have the highest possible rate at that point, but we only have access to a few. Nest balls, however, can be easily bought at the pokeball store.