Here's the problem. If you want to have one train entering the loop while another one is leaving, you have polarity switching all over the place if the loop itself is the reverser. I prefer to have one of the approach tracks, either in or out, be the reversing section, so all the trains in the staging loop are "on the same page", and you can peacefully run trains in and out of staging simultaneously.
As was pointed out elsewhere, if the dude is running lighted passenger consists, the reversing section needs to be as long as the longest PASSENGER train. Freights don't need any more than a few lengths more than the engine consist.
Lee