Here's a fairly representative image of what I'm doing.
The only thing that I'm doing that might be considered weird is putting the same 1 second timeline between each actual piece (they wanted black between their videos and this was the quickest/easiest way to achieve that result).
For Example a playlist would include: Timeline 1 -> 1 Second Black Timeline -> Timeline 2 -> Same 1 Second Black Timeline -> Timeline 3... etc etc.
Or maybe the fact the playlist End Action is to link back to itself?
I'm hoping to have some time tomorrow to fiddle with these two possibilities and re-test.