Late Roman Unit Sizes

[Flavivs Aetivs]

There's no way a standard Ala could be 60 men. The ratio of infantry to cavalry in the army would be incredibly skewed. Over 95% of the army would be infantry, at least.

I think many of these forts were detachments of units, with others in nearby towns and cities. Don't forget, the de metatis law points out that Roman troops were quartered in houses too, not just forts.