Zeal won't help for crafting, as there's a penalty for failure (losing the materials) and you can never take 20 if there's a penalty for failure. There are certainly a few good uses for it (escape artist is an obvious one), but that's about it.
Also, you don't really need it for forgery anyway. A single rank in that skill and then taking 10 is enough, with Cunning Knowledge. Remember, it's Int based and Forgery is always opposed by a Forgery check... have you noticed how few NPCs have ranks in that skill? So a 10th level Factotum with, for example, a 22 in Int (very reasonable) and a single rank in Forgery, plus a Forger's Kit (+2) can, once per day, create a forged thingy and automatically get a 29. Virtually no one is going to even have a chance of beating that. As such, you can forgery your way through virtually anything... it's always fun to forge orders that the weapons wearhouse guards have to equip you and your men appropriately, for example.
JaronK