The word efficient means working well or producing a result with little to no waste of time, money, energy, or resources. It describes people who do tasks with skill and speed, or things like machines that use fewer resources to do their job

So most efficient would be for one person clean up behind the sweep (while it is running) while also moving truck as needed.  Any other method would result in more man hours and would be a waste of time. 

Of course it not executed properly could result in running the truck over which would not be very efficient. So, at the beginning of a load get in bin and clean behind sweep until a couple of minutes before you need to move truck. Get out of bin, watch and move truck, get back into bin right after moving to back hopper.  To help with timing this right, might want have a timer of some sort. With most sweeps that go around on there own, would only need to shovel and sweep for 2- 2 or 3 minute periods per truck load. 

How large are your bins?  I see no way in our 42 feet bins to get everything shoveled to the sump in 30 minutes after letting the sweep go around just once, especially with how much is left at the wall, like more than 100 bushel. Biggest reason to clean behind sweep is that sometimes what the sweep leaves is lower quality and can get docked when not mixed with rest of grain. 

Anybody have a number for how many bushels are left after letting sweep go around once? 

When sweeping after sweep is done do you run the auger the whole time?

We clean behind sweep and will shut off auger when doing the last little bit, pile grain on top of sumps and then turn on augers for around 7 seconds.  Normally do this 3 or 4 times. Always have at least 2 people for this step.