1. i wait until the majority are settled. how long that takes depends on how well they went into the hive in the first place and how many are out scouting. you also have to watch that while you are waiting for them to settle, they don't decide to up and leave.
2. very often i have had to leave before dark and take the hive. if i KNOW i have the queen and have gotten the majority of the bees, i warn the homeowner that there will be returning forages for a couple of days, even a clump or two of bees. some Bee Quick is helpful here. it helps discourage them from hanging around.
communication with the home/land owner is the key, but i have had a couple of call backs because of a clump that wouldn't leave.
3. you have to do what you have to do. my preference with a swarm trap is to pick them up after dark even if that means they have to sit for a couple of days. i put swarm traps up at my friends berry farm. i might go by and check them, but if i don't have the truck and they are full, i'll leave them for later.
everyone does different things. most of my calls seem to be far from home, so going back and forth is not practical. i find that as long as i have explained things to people, they are good with a few bees hanging around for a couple of days.