Mike, here's the interesting thing.  Since I'm using very flexible rubber
hose of the type you might find on vacuum lines, which kinks easily, just
the slight weight of the rubber hose hanging down kinks the hose where it
leaves the bolt.  As long as the engine is just idling, the coolant does
not force its way past the kink.  When the engine is revved, the coolant
does flow past the kink.  This feature was not planned, it's entirely
accidental, and I believe it's due to the fact that the system is not
pressurized, coupled with the properties of the hose I happened to use.
Vinyl hose, being  considerably stiffer, would likely not self seal by
kinking like this.  Consequently, there is no need to run back and forth;
when the engine is idling, no coolant is flowing throught the hose, and
even if it were, it doesn't matter as it goes into the bucket.  What I
formerly thought was better accomplished with a second person, is now a
leisurely operation for me alone.