I did some bounce off the side of my house and did some rotating of the flash so it wasnt so direct. for the family shots it will be anywhere between 4 and 30 people. i wont have any assistant just myself and the 600 strapped to the top of the 5d. it may be outdoors or indoors. i want to do indoors for flash purposes.
One flash will have a tough time trying to light a group of 30 people. Basic things to keep in mind are that the bigger the light source, the softer the light (softer = better), and light from above or the side are better than straight on. If you have white ceilings that are low enough, point the flash up and bounce off that - a ceiling is a big light source (if colored, though, it will color the light). The 600EX-RT has a catchlight panel that you can pull up to throw a little direct light when you bounce, that adds nice catchlights to the eyes.
lens wise ill be using my 16-35 2.8 ii for the larger family shots and probably 24-105 for the rest.
Both are good, make sure you use a deep enough DoF for a group. Also, if you go wider than 20mm and you're using direct flash as fill outdoors, pull out the wide panel on the flash.
Is there any obvious setting on the 600ex to change or just stay in ettl mode? i also see im restricted to 1/200th of a sec and i realize that it doesnt matter because the camera is just playing off the flash in terms of shutter release. I think that is right?
E-TTL II works pretty well, but I often find I need a bit of FEC. The 1/200 s max shutter results from the max sync speed of the camera shutter. The workaround is to use high speed sync (HSS, the camera fires a burst of pulses instead of a single flash), but that limits your flash power. Wouldn't be needed indoors most likely, but outdoors if there's bright daylight you might need it for an f/2.8 shot (unlikely with f/4), it's most useful for shooting fast primes wide open outdoors, although I usually need an ND as well.