I have created an LJ conditions link page, with explanations for conservative "fishable" swell heights.
Big swells with long periods (>14 seconds) don't really affect the LJ Shores launch at all - as the canyon walls will refract the energy to Blacks and the Point - but, will affect all other SD beaches greatly.
Big, short period swell (less than 10 seconds) can make the LJ Shores launch dicey.
Your mileage may vary.
http://www.larryl.com/favorite_kayak_conditions.htm