to stay a bit longer in “nit-picker” modus:
i think, that there is an underlaying languageproblem.
in german there is the word “Spurweite” (trackwidth) (today shortened to “Spur” (spoor))
while in english we all use the less specific “gauge” (guage).
and in 1:1 there is used the word “Standardspurweite” (we love long words!) - 1435mm.
when the model/toy train standards were created - (and i don’t believe the old rumours, that the question, if it was first pronounced in england or in germany might have been one of the reasons for WW1) - they were the same. 1,2,3 (in germany written in roman numbers I; II; III)
i do ignore, when the number four was added.
later the smaller scales came. first the “zero”, then, between the wars, “Half zero” and so on.
these first standards all referred to fixed ratios (scales) and gave the width of standardspurweiten (standardspoorwidths) for each.
additional they created letters for different narrow gauges inside the scales. “m” for Meter, “n3” for 3 foot, “n2” for 2 foot and “e” for Half-Standard and finally “i” and “f” for field- and industrial trains.
(that is why germans call LGB a 2m (IIm) scale)
in my eyes your mentioning of a dropped gauge 2 does not look reasonable.
because the “spurs” are well related.
(english) “zero” 1:43.5 is double “half zero” 1:87
“two” 1:22.5 is half of (german) “zero” 1:45
“S” (former H1) 1:64 is double “one” 1:32
“three” 1:16 is half of “one” 1:32
“one” is about two thirds of “zero”
“two” is about two thirds of “one”
if 1:22.5 would be “Gauge 3”, where is then “gauge two”?
one of the latecomers dollhousescale 1:24 or 1:29?
(it can’t be Fn3 in 1:20.3 - that is too big)
/rant & putting away the Lederhosen again. 
