As it's fairly symetrical I'd say it's up to you, bend before or after getting it to about 75% tillered.
It's all about learning new techniques and getting experience. Don't go mad with the bends, and you''ll be fine.
My biggest bending mistake is to not allow sufficient time for the wood to settle back down, so be warned, leave it at least a couple of days, 3 to be really 100% safe. Some wood just likes to go back where it started, other staves just do whatever you ask of 'em.
Have fun
Del