Hello Joe;
Visit this site:
http://www.asnt.org/certification/cert/typesearch.cfm?State=CA&Program=A3&srchrnm=submit&Country=It lists all the ASNT ACCP Professional NDT Level IIIs in California. It also lists the town or city where they reside. Find a couple in your area and contact them to see if they would be interested in working with you.
Getting a good Level III is like finding a good dentist or doctor. You don't look in the newspaper to see who has a sale going on. You need to build a relationship with them so they know what you are doing and they understand what your needs and product line are. It isn't a one shoe fits all situation. You may even go through a couple of Level IIIs before you find one that suits you feel comfortable with and suits your needs.
Shopping for a good price is money wasted. You need someone that can work with you to develop a good NDT process. Someone that is local to your area will be much more useful to you than someone like me that is three time zones removed and not in a position to sit down with you to actually discuss your circumstances, product line, code requirements, customer expectations, etc.
Now, why am I suggesting searching out an ACCP Level III? Simple, because the ACCP Professional NDT Level III has passed a third party examination demonstrating a certain level of proficiency and they had to write a NDT procedure as part of the examination. Like the CWI or the SCWI, the ACCP Level III has to subscribe to a Code of Ethics and there is third party involvement. Like the QC1 program operated by AWS, the ACCP operated by ASNT is recognized world wide. When I took my Level III examinations, more than a third of those sitting for the examination were from other countries. That tells me it is a recognized program and it has value.