We are only just starting our first engagement program but here's what we have set up (not all have content or active yet)...
We have a prospects nurture program with 8 streams (these are 4 different stages and each stage has a cloned stream for INTL, so that these may be delivered at a different time).
We have about 5-6 pieces of content per stream and most of these are A/B testing so about 10-12 emails.