HHV gearing/etiquette Qs

@Sumo: I was prepared to learn about gear inches until I learned it was not the actual distance travelled per crank revolution, but the distance you would travel before crashing if you rode through a temporal anomaly and your bike suddenly turned into a penny farthing, or something ... then gave accepted wisdom the benefit of the doubt, but ultimately read:

For bicycles with 700c wheels, some cyclists quote gear inches based on a nominal wheel diameter of 27 inches ... the rolling diameter of a 700c wheel may be significantly higher or lower than 27", depending on the tire size, e.g. nearly 27.5" for a 700x38 tire, or just over 26" for a 700x20 tire. This can be the source of some confusion when comparing gears unless it is clear whether gear inches have been calculated using the actual wheel size or a conventionalised 27".

...and gave up. I suspect I am not alone.