Jeff,
I must second Ian's opinion.  I currently have long probes for the
"inboard" part of the tank and short probes coming in from the tips for
the "outboard" portion of the tank.  I use two fuel gauges on the panel.
 The inboard probes start reading sooner than I was expecting in terms
of time since top off. Originally I was thinking the way you are now,
wanting to see needle movement right from the start.   Now, if I ever
have need for panel space for a new toy, the outboard fuel gauge is out
of there.
Chris Zavatson

>>> ian.crowe@sympatico.ca 03/03/03 06:45PM >>>
I too have the extended tanks but my  Skysport probes only go out to
the original tank bulkhead.  This is the bulkhead that houses the
aileron bell crank.

My experience has been that the tank gauge starts to read quite
quickly.  You only have 5 gallons in the extension for a total capacity
of just under 21 usg per side and the dihedral angle which causes the
fuel at the tip to be higher than the inboard end is not so high that it
creates a large dead spot in the gauge reading.

If you are a purist you have to fit the extended probes but it will not
significantly improve the accuracy of the gauges.  I had gauge wiring
problems and I wanted to recalibrate the gauges.  I filled one tank up
to the filler and set the full trimmer, I then pumped this tank into the
empty tank after setting the low trimmer.  What was interesting was that
the when one read 3/4full the other read 1/4 full and this worked at 1/2
and 3/4 going the other way.  I concluded fom this that the system was
linear.  Incidentally I then set the full probe on the tank I had just
filled and the empty trimmer on the tank I had just emptied and refilled
it.  Again the two gauges worked exactly in step.

Up to you of course but for my money I would not bother to spend money
needlessly.

Ian Crowe