I would just feed him around 7ish at bedtime. Tracy suggested combining cluster feeds by 8 weeks to be on a 3 hour EASY, so if he is established on that I wouldn't change it now. If he seems hungry earlier than the 3 hours in the evening offer him a feed and then top him up just before sleep. Formula is different to breastmilk as it takes longer to digest and many women produce less milk in the evenings so bottle fed babies often don't want or need to cluster feed.
HTH!
Laura