[split] Distances between files and ranks

[Nathan Ross]

Maybe Frontinus rounded the 28 deep to 30 deep, so as to save time and explanation

Well... maybe! But I think we have to assume that the sources mean what they say, and not that they made mistakes, altered numbers or fudged things, just to suit our own theories.

Following these examples, where would you place the archers and slingers.

At the flanks, or the rear, or in gaps between the other units, or ahead of them - anywhere would be fine really.

Your Frontinus quote, meanwhile, does indeed suggest that light troops were incorporated into legion subunits. How that was done is not clear; nor is it clear whether this is a permanent alteration or a temporary expedient. If Frontinus mentions Scipio doing it as a 'stratagem', it probably means this was not standard practice, and few other commanders did the same.