The most common posting rule used is that someone can post after two more people have posted after them. For example:

- Me

- Crimson

- Archmage

- Me again

Of course you don't HAVE to post again if you don't want but as long as there is at least a two person break between your posts you're good to go. Allot of people go with this amount and it works regardless of group size. Too many breaks between means waiting on more people which could then mean slower pace and even a complete stop if more than one person has a busy IRL issue to tackle. I would strongly advise keeping the post break to two people.