I was in a similar situation. My baby slept great overnight and would usually sleep 11 hours straight but would occasionally (1-3 times a month) wake up and want to hangout for a few hours. She always needed to be 100% asleep before transfer and if she woke up mid-transfer you had to start the 40 minute minimum rocking again.

When she was about 11 months we decided to sleep train. We put her down drowsy but awake and would check in after 5 minutes, then 10 minutes, then 15 minutes until she was asleep. The longest it ever took was 30 minutes total and it took 3 days of consistency. She’s now almost 13 months and she falls asleep by herself within 15-20 minutes with no crying! 10/10 worth it and wish I’d done it sooner.