I've stayed out of these various 'bleeding' discussions for a long time,
but have to throw this in.  The local VW dealer did a lousy job of
bleeding my '85 1.9l on one occasion. At that time I was parked in a
steep driveway (to my basement garage) and noticed a lot of gurgling
noise from the engine compartment just after shutting down the engine,
parked nose DOWN.  It dawned on me that a couple of things were
happening.  First, with the nose down all the bubbles were coming to the
engine area with the engine off.  Two, the overheating was creating
steam bubbles that were collapsing as the engine cooled.  I opened the
engine compartment, topped off the overflow tank, ran the engine until I
could hear the bubbling up front, shut down, and waited while the
coolant cooled.  As soon as the system started to suck fluid from the
overflow tank (steam condensing) I popped the pressure cap on the main
filler tank and proceeded to feed it all the pre-mix it would take.  The
bubbles were very noticeable coming out the filler tank and as the
engine cooled and the steam condensed I just made sure it didn't have a
chance to suck air, only coolant.  I used this same approach at least
two other times with the '85 when I had lost coolant on the road due to
a leaking coolant pipe.  I doubt that this provided a 'perfect' bleed,
but it sure got most of the bubbles out.