I very much suspect you guys have beefy legs that are more comfortable with lower cadences, as I've always found mid rings of 39, 40, 42 to be too tall for loaded touring, and 36, 34 and 32 rings just seem to work better for my legs for those mid range speeds we are most often going, let's say 15 to 25kph.
i think 60 is my about my minimum cadence and i would be amazed if i ever got over 90 for more than a short blast up a hill or out of the way of traffic. i will say i rarely use the granny. in fact when i put the granny on i got a steel one to make sure it would last. what a ridiculous thing to do considering how seldom i use it.
pictured is my half step and granny rig. i have since changed out the nuovo record rd for a long cage 105.