Perhaps I misunderstood. I thought you were asking me a more general question about point systems, and whether or not they could be applied to Lasalle.
If you're just looking for a way to calculate skewed-odds games, such as 3-vs-2 sorts of things, then I guess I'd have to say that each Support Brigade is "one point," in the sense that they're supposed to be more or less of equal value.
That said, I was also cognizant that there was a sort of feel within each army and each period, that might render some types of brigades "worth" more or less than in other armies or periods. French cavalry in 1813, for instance, isn't much of a bargain. I couldn't think of any other way to do it, since I didn't want to create the false impression of either (A) lots of French cavalry in 1813, or (B) good-quality and large French cavalry units in 1813. Spanish cavalry is another example where I had to stretch in the opposite direction just to rationalize giving them enough to be worth taking the choice.
Additionally, we decided not to think too hard about the implications of placing any given choice in the context of other choices that might or might not be made for that army in that period. For example, is a brigade of Dragoons "worth" more to a Peninsular French player simply because he can't choose Cuirassiers? Or do the Dragoons have their own inherent value based upon things they give you (the Pursuit ability, for instance), that make it irrelevant whether or not you could choose something "better" ? Does a question like that carry more weight when you play with multiple support brigades... or does it carry more weight when you have only one?
This brings me back to the French cavalry in 1813. Compared to the choices for French cavalry in, say, 1812, it's crap. But you've got to have SOME cavalry, so you'll have to settle for this wimpy stuff. Given the choices you have in 1813, it's "worth" it in that sense, that it's better to have some cavalry than none. Presumably you didn't pick a French 1813 army because you're a cavalry fan. Presumably there was some other attraction that made it "worth it." (I can't remember the name of the guy on this forum from a couple of weeks ago, who predicted that the sure-fire winning army in Lasalle was a mob of conscript infantry all bunched together, but perhaps he's a good example.)
We recognized that the ostensible utility of point systems was their total neutrality: they detach you totally from any historical considerations about "balance." So for example, if the British army developed certain abilities in response to always fighting the same enemy (France), then you could argue that their army is very "balanced" against the French, but not necessarily against, say, the Austrians. But I decided not to worry too much about that, since people playing a wargame are going to impose their own kinds of balance against their own opponents, and are also presumably going to choose armies that reflect and reward their own preferred playing styles.
I was thinking of those old Ancients / Renaissance army lists by Phil Barker. Being an Ottoman Turk fan, I was always delighted to see that the Ottoman list included pretty much every kind of unit on earth. But of course nobody who ever created an Ottoman army for that game ever created anything that even remotely resembled the Ottoman army in history, because who would want to play against you when you're allowed to bring 200,000 men onto the table!? So the Turks got bathtubbed down to some sort of "greatest hits album" version of their army, just to keep it balanced on the wargame table. So one of the most important historical considerations of real-world balance - that is, Size - is rarely replicated.