From what I've read elsewhere, most managers charge 10%, although a substantial number do charge 15%. That could be completely wrong, however.

Also, my understanding is that a manager is barred from taking the 10-15% commission on a project if they take a producer credit. They can only do one or the other, not both. True?

Paul, mgr fees are negotiable between 10-15%, but in my experience, at least with the writers I know, typically 15%.

Re your second point: That's my understanding as well. Mgr rebates their commission if they produce. No double dipping.

Most managers, (including my own) especially at the A-list, firms charge 10%.

Many writers also have a business manager/accountant who get 3%.

Phew, that is a lot off the top.

In Uk you just needa literary agent - who can charge up to 20% for the privelige. But that's it - no managers or lawyers on top.