Looking at the sprue, it looks like 24 archers are possible.
Plus 2 spara per sprue, so 16 big shield blokes!
Looks to me like, if your were making early Persian units,
You can field a spara unit of 32 in 4 ranks of 6, with the front rank holding the spara.
Giving you 8 figures spare as javelin skirmishes perhaps?