My method of serving pasta and sauce at an event is partially dependent on how long its going to have to sit around.
If its a long transport, I'll make extra sauce, saturate the pasta somewhat to keep it moist and meld the flavors, then
15 minutes before serving I add the rest of the sauce.
Another way I have done it is to keep the pasta and sauce separate--pasta sits in shallow water (1 sterno) then is tonged out
for service, sauce is plopped on top with a 4 oz ladle. This works especially well for a staggered, or extended service time.
(And there is also a significant percentage of guests who prefer their pasta to be served this way.)
And of course, I'm talking about an action-station service with this method. I never ever put pasta and sauce out separately
for a self service buffet. That's a sure way to hear "we neeeeed more sauce!" about 8 minutes in, only to find all the sauce
drained, with 6 lbs of dry pasta next to it with no sauce available. Lack of consideration in the presence of hunger and tasty
vittles is part of the human condition. We must endeavor to fight it off with our very being! (and smart methods maybe)