SirAlbert said:
The fact a Bonaparte was in the throne doesn't mean the army was by his side.
That's why they're rebels. They were rebelling against King José. He certainly was king, though. Never mind if he was unpopular, not particularly competent and didn't deserve the position, he was still as legitimate a king as any English monarch has ever been. His kingdom was still the one and only Kingdom of Spain. Do bear in mind that Ferdinando VII's House of Bourbon had effectively been installed by the French army in the War of Spanish Succession. The Spanish were getting a Frenchman either way.
Anyway, the Junta Suprema (I do know where adjectives go in Spanish, by the way) will mostly get British armed and uniform militia and regulars. The guerillas hadn't started operating with the Spanish army yet, so they'll be there own faction. The Spanish army was in a very disorganised and transitional state at this point, so they will have some older uniforms, as well, to help show that.
I haven't exactly decide on how I'll do the guerillas yet, though. I want them to roam around in small bands like looters, but I was want some of the more famous leaders as proper lords. We'll see.
James Grant said:
...most were untrained peasants and had little uniform or in some cases weaponry....
Just because the British regarded them as such doesn't make it the case. By the time the mod starts, the British had already shipped 90,000 uniforms, 200,000 muskets and half a million yards of cloth to the Spanish. Combine that with the older uniforms and new of Spanish make I have a hard time believe they were un-uniformed or badly-armed. Perhaps they had been at the very start of the hostilities, but the fact that they won several battles against the French in 1809 (far more than the British did) proves they were a competent force. Badly officer'd in many cases, but usually good soldiers.