You should be able to check tint laws on the state government site. But to my understanding, it's pretty restrictive. Looks like nothing allowed on the front (minus 4" strip at top), and at least 70% transmission on the front. I could be wrong but that's what I got from a quick Google search. Sounds like most tint people want to run isn't technically legal.
I have 30% on front windows and windshield. It basically matches the rear. Not in California, but technically too dark. I think there's a natural limit of what law enforcement might "allow". That's usually enough to see you without the whole truck being blacked out. As long as you're somewhat visible, you should be okay.
You could also call your local tint shop and ask them.
