specifics in Spear fighting combat

[PMBardunias]

I have a suspicion that only selected sections in the line opened, vice every other file. That's how I'd do it--create one file opening per forty or so, and let the psiloi/Velites file through. That way, even if pursued, most of your line is solid as a rock.

Or between units. The fate of units in battle is suprisingly independant, with adjacent units often showing one unit breaking and one standing. This indicates, perhaps not suprisingly, that the unit cohesion is greater than the line cohesion. The joint between units would be a natural place to form lanes for the passage of light troops.