Maybe I should say...generally he is up for 1 1/2 hours, and down for 45 minutes...I watch for his tired cues to put him to sleep. He takes 10 minutes to feed, and feeds every 3 hours or so through the day (4-6 hours at night).

Maybe thats a pattern...?
Sounds like an amazing rhythm. Fantastic, and one that I would be jealous of . I know there is a stigma about the 45 minute sleep cycle. But sounds perfect for an 11 week old.

For example, when Jovie was 11 weeks she was awake for around an hourish, and when I noticed she was tired I would rock her to sleep and she would sleep around an hour. Sometimes it would be 30 minutes, sometimes 60, but rarely over an hour.

I generally just watched her for cues, jerky movements, yawning, rubbing eyes/ears. At night we have a set routine of dinner, bath, quiet play and then settling in bed. Either a story or a massage or something to quiet their spirits to sleep. Jovie refused to feed to sleep so I woud do a quiet feed in our bed with the lights out & then cuddle her to sleep at night, or I would put her in the hammock and rock her to sleep after the feed.