*** How do you measure BOTH SIDES with a piece of wood, if the first side you measure holds more than the second side, and has wetted the wood?
*** Surely the wood absorbs a lot of fuel and either smells, or is a fire hazard in the cockpit.
The petrol actually evaporates pretty quickly, so when you get the to other wing during your checks you can be pretty sure a wooden dipstick will be dry.
I've only ever used wooden ones, and never had a problem, although I do agree that you shouldn't leave the dipstick in too long if you want to get an accurate reading.