2/3rds for ranger cl, 1/2 for wizard cl.
This would allow you to go 15 ranger/15 arcane archer and get 25 cl, or 20 wizard/sorc 10 arcane archer for 25 cl. Neither build would be overpowered. The wizard would probably never get played, and the rangers companion would still be weak enough where going full ranger is probably still better. But it would allow the AA to cast spells as opposed to aiming for mundane territory, which makes some sense for a class that was designed to be magic and archery.
Thanks for reading.
