Thereare no salad greens that I know of that can withstand being dressed 2 hours before serving, no matter how light a viniagrette you make. But here are a few options:
1. Dressing served on the side
2. Plate salads without the dressing and just before guests sit down have servers go around and drizzle the salads with dressing (not optimal but way better than dressing the salads 2 hours in advance)
3. Create a salad that made up of vegetables other than greens such as beets or other root vegetables and then toss with just a bit of frissee, which would somewhat hold up for that length of time.
Could I suggest that in the line where it says "topic" you write the actual topic? That way we can know if we are interested in what you are asking or not, if we have any expertise or not. Like you might say "dressing salads in advance?" as a topic line. It makes it easier. Notice the other posts. They all have an actual topic, which is preferably not "help" or something generic, but specific.