I agree about team size, 3-5 is good, any larger and people will start wandering off on their own or create cliques.
I'm also not a fan of "sync standups", that's micro management garbage. A three minute 'i'm blocked, who can help?' or 'no blockers today' session, that's the sweet spot. If someone wants a report on progression and so on they can book a meeting with a clear agenda in advance and the relevant people can prepare and do a succinct description of where they're at. No meeting that takes more than five minutes and doesn't have a set agenda should ever be held.