If you are in SLOtown, we are both on the central coast. I'm 90 miles south.  Good to have you here!

I would be shocked if a taxpayer didn't have to withhold until receipt of an FTB notice. Shocked I tell you.

The chart at 29-201 has the answer.  Withhold and pay quarterly.  It is page 325 of the 2022 edition.

Consider the group composite return which allows the LLC to withhold.  See page 328 under the heading Waivers and reduced withholding.  The composite return makes withholding easier by avoiding the withholding on individuals. I have not done a composite return in a long time.