Don't you have "Day labor" services in Cali?
We just call them, tell them what we need, they provide and charge us by the hour per person, and they take care of EVERYTHING else (transport, paying the labor, ALL legalities, paperwork, workers comp, etc.)
They can provide either skilled or unskilled, a single day or months at a time.
No money EVER changes hands between the supplied labor and us, we pay the services directly (on a monthly basis).
Works great when added grunts are needed, and all "day labor" services are licensed and regulated by the state.
Here they can even provide labor for homeowners.