Unless you have an approved Research Report from the City of Los Angeles, you cannot build with SIPs in the City of Los Angeles. Second, the cost of SIPs is actually cheaper than conventional construction in the Los Angeles area. You cannot fabricate your own panels and expect to get an approved inspection. The panels must be engineered in order to get a building code approval and, the panels must be fabricated in an approved facility to meet the current building code. On-site fabrication is a no-no, especially if you do not have the experience and tools to not violate any of the engineering constraints.
We have built over 30 projects in Los Angeles and I would strongly discourage your attempting to do anything that is not strictly legal in Los Angeles County.
Lack of experience and knowledge is a very 'costly' combination - hire a professional and pay for it to be done 'once' and done 'right'.
GFR