I find the tops should be about 6.5 to 7.5 inches further out than the bottom as a good baseline. Some people will go further out, depends on handles and flying preference, but the above is a good baseline. I don't believe there is any merit in going less than that on standard equipment unless you like to hold the handles at the bottom or something really obscure.
I pretty much use one of two knots on my top leaders which cover me from light wind to overpowered. When handing off to someone who wants to give this flying thing a try, I will usually drop only one knot back on the top for them to make it a little easier, but that's usually only when I'm on my heavier brake setting in lighter wind. Failing that scenario, I leave it right where I fly and give them the handles.
Once you show someone how to launch correctly the setup is not a problem.