Very Small Units
How would you best represent less than battalion size units on the table? I'm thinking of the Guards, Hanoverians and Nassau at Hougoumont, where they might just be a few companies strong. I have thought of combining them into a single unit(s) or having a battalion stand for each but with a lower CR, or even have single figure stands to represent companies, similar to the 95th Rifles.
I guess the answer really depends on how the Units in question are meant to function. While some historical Units might be "just a couple companies strong", it really isn't the size so much as the use case that should dictate using a Specialty Unit vs a regular Unit. For instance, Russian Converged Grenadier Battalions are *normally* only three companies, but… they fought and functioned as battalions. This could be contrasted with say, Spanish civilian levies that have just received their weapons, haven't been trained, and they are really just a big mob made up of a bunch of small mobs… and might be better suited to be treated as Speciality Units (perhaps without any specialties :-p).
Does that help at all?
That does help and thinking in those terms then I would say that the Hougoumont defenders were acting together as a battalion, despite being made up of a few companies.