I can't refer you to anyone.. I'm on the wrong coast.. But you can get a listing of them at: https://designee.faa.gov/#/designeeLocator
You want to search for DAR-F's with authorization #47. You have 12 to pick from in CA.
I don't know if he would travel as far as you, but Scott McDaniels, former Van's employee who had a hand in a lot of the RV-12 design/parts, is now a DAR for hire. Might be a long/expensive trip for him from Oregon.. but if you want a blessing from someone who knows everything about the RV-12.. he'd be your top pick.
Rob Carsey, Winfield Park, NJ
RV-12iS (N713) / Completed 12/2020 / 510hrs and counting
ASEL, Glider, AGI/IGI, LSRM-I, FCC GROL
or ADSBExchange Track