Dwell meters, dist problems

["Weidenheimer Allan P KPWA" <weidenhe@domain.elided>]

I have a meter from Fluke, it is specifically an automotive
model (I forget the model #).  It has both a clamp on lead
to measure RPM, and a mode that measures the duty cycle of
the voltage across the points.  There ar charts in the manual
based on the # of cylinders that cross that duty cycle to 
degrees of dwell.  It is a very nice meter for auto work.
It sounds like some of you repeatedly put the dist cap on
and test the dwell?  I just connect the meter, ground the 
coil HV wire, and crank the engine, moving the points while
it is cranking, until it is close--it oscillates some during
the operation.  Tighten the screws down, and check it again, 
because some points manufacturers don't get them bent quite 
right (flat one the bottom, when the screws hold them) and 
the adjustment may move when you tighten them.  After that,
I put the cap on, and reconnect the coil wire.  I carry
feeler guages for a field emergency, because I don't 
carry the meter with me.  Of course, now that the truck has
a Pertronix, I only need the guages if it were to fail...

Along all these dwell problems, I think I'm having one on a
non IHC vehicle.  I think Michael posted something about
an old mechanic in New Mexico? showing him how the top
bushing was shot, and occasionally causing the points to 
not open.  It only happens to me when I am cruising at an
even, steady speed, usually under 50MPH.  The ignition
just 'shuts off' for a second, then it comes back.  I noticed
that the little button in the top of the distributor cap
is not worn in one spot, but the wear extends down the sides.
I can move the top of the shaft a fair amount, and I am
theorizing that when the ignition dies, the shaft has flopped
so that the points are not opening.  This is on my 307+ KMi
66 Mustang, which needs to get me home from the airport
tomorrow night.  So, I plan to remember what that mechanic
showed Michael, and open the gap some if I have a problem.
AFAIK, the distributor is original.  The engine is recently
rebuilt, but I re-used the distributor.  Does this theory
sound reasonable?

Allan Weidenheimer