I must be on the other end of the spectrum, as I find his gear ranges a bit to conservative
No panniers: 33 to 110″ Needs at least 119" on the top end
Panniers with 5kg: 29 to 110″ Needs 119" on the top end, or I would spin out with a decent wind behind me
Panniers with 10kg: 25 to 110″ This would be about right I would say, but I might want a bit more on the top end maybe 115"
Panniers with 20kg or more: 20 to 100″ I have ridden with this weight but not touring, I think its about right though, 20" is plenty low enough
Off-Road Touring: 18 to 100″ 18" is plenty low enough, infact on my steel tourer when I click down to 18" I have to spin my legs so fast to just stay upright. I never use my lowest gears, I don't feel the need for them.