We may have submitted preliminary notices without an estimated contract value and would like to know what our next steps are.
California preliminary notices must contain an estimate of the total price of the work. Levelset discusses that here: What Information Is Included in a California Preliminary Notice? This amount doesn't necessarily need to be exactly dollar for dollar with the amount that's ultimately billed, however. A good faith estimate at the time the prelim is sent is generally what's required, but it's best to be as accurate as possible to avoid any potential issues.
Regarding past preliminary notices that don't include required information: It might be a good idea to consult with a CA construction lawyer about how to proceed, since they'll be able to provide legal advice. But if the amount isn't included on CA prelims at all, the validity of those notices may well be called into question. Note that sending late notice may be an option for some CA claimants since it will still be partially effective. Further information on that here: What happens if I send a California preliminary notice late?