Jim, Not perfect but useful . . .
Fuel resistant transparent plastic tubes can be used as a dipstick. You dip it and put your thumb over the top of the tube, lift it out and see where it comes on your pre-calibrated marks. With the slant on Coupe tanks, you'd only be able to measure the (wild guess) 7-18 gallon range in the wing tanks. The slant makes the lowest gallon range hard to measure because there's no fuel under the filler cap. To calibrate, I'd drain both wing tanks then put one gallon in each side and measure and mark the tube. Then add two more gallons and measure and mark the tube. This is also a good thing to do with the nose tank. I was astounded to find that with my particular nose tank cork and gauge, I had 3.5 gallons when the wire was all the way down. Naturally, this needs to be repeated occasionally since sometimes corks that aren't sealed well enough get saturated and float lower. (When they sink in flight, it gives a really good pucker facter - I can tell you from personal experience!) I, too, would be interested in ideas better than this. Ed
