We'll have to make you an official "California Guy".
Out here in Seismic Area 4, we use the Caddy IDS hangers that you recommend for just such an application.http://www.erico.com/products/CADDYcfcIndSprtClps.asp
They're of extra value when the layout of the fixtures, lighting track, etc. don't fall right on a main runner of the grid. The cross tees are comparatively weak and the IDS support clips can provide the support for the fixtures no matter what the layout.
Usually the GC will have the ceiling contractor shoot the additional support wires and seismic splay wires. If not, a case of beer or 2 to the ceiling guy seems to do the trick