Owners/partners have the option to opt out, they are not ineligible. A friend of mine has a businesses with him and his uncle, they are both partners and are therefore exempt from having to carry WC. The only problem with this is that in this day and age, the majority of customers don't give a fahk whether or not you are legally exempt from having WC, they want you to have it anyway. My friend thought he was all slick circumventing the law, until he started getting denied on all his bids because he didn't carry WC even though technically he wasn't required to. The best thing to do, (and you didnt hear this from me) is apply for the min coverage of WC available (based on payroll projections) and then don't pay yourselves an actual pay check past what you signed up on WC for. When you get your end of the year audit, you'll be within the minimum threshold, and not have to pay a ton back to the agency. This way, you have coverage to show your clients, and you aren't paying through the nose. Now I know CA has one of the highest rates in the US and that it borders on the absurd, so I do not know what your min is there. But relativey speaking, the min WC coverage here in MA is an easily dealt with expense, and pays dividends in the long run by how many more jobs you will be able to pull with having it.
In this situation, you'd consult an accountant, not an attorney