Hey guys. Just saw this thread and I am available to help you with historical information. I'm from Portugal and my specialty is classic history, particularly greco-roman history.
But if you want information regarding Iberians, they lived in small tribes that descended from the celtic invasions. They were skilled hunters and lived from the land, although the Iberians tribes, specially the ones from the south, had a degree of culture and knowledge that surpassed by far that of the Germans, Gallic and steppes barbarians.
You see, since around 600s b.C. they came in contact with Phoenicians, then Greeks, and after that Carthaginians. Ironically, the various colonies from different origins coexisted in relative peace with the local tribes. But those tribes were not very homogenized.
While there were the southern and eastern more developed tribes, there were also the north/northwest tribes that still maintained much of the Celtic culture, specially the lusitans. They're skirmish tactics, surprise attacks and constant traps and ambushes (they were indeed the fathers of the guerrilla warfare) kept the romans away for decades. Only when the romans bribed the lusitans commanders, friends to their leader, did they manage to defeat them. Go google Viriatus. He's still a figure of much respect here in Portugal and in Viseu, the city where their main settlement was, there's a statue of him.
So, my advice: Iberians were superior to other barbarian factions do to their constant contact with greeks, carthaginians and phenicians. They were also skilled warriors that excelled in hit and run and ambushes. One other fact that not many know about: they were the inventors of the gladius, well before the romans copied it from them. Around 4 or 5 b.C. the romans came into contact with the iberians and saw how they used missiles before charging with double bladed thrusting swords, and so they grabbed the idea but used it with heavy armored troops (which was something that the Iberians didn't do, because of the rough terrain and high temperatures of the region. Light armored troops were preferred). Which is also funny, since Iberia had a lot of minerals, particular bronze, iron and copper.
Oh, and while they did not used horses that much, the region also had some of the best horses in the world (still does nowadays). Often the imperators used Spanish horses for their strength and size. Even today the lusitan horses are worth more than some BMWs.
So yeah, you can pretty much throw anything at the iberians. Spears, bows, slings, javelins, gladius, shields, etc. They were the kind to use just about anything. But do avoid heavy armor as much possible. Maybe one or two units. More wouldn't be too accurate. They were very found of leather (the region was a great place for cattle).
As economy goes, I already mentined minerals, but there was also a lot of fish, olives, wine, cattle and fruit. Grain not that much, but some. And horses, don't forget horses
If you have any question or need further clarification regarding anything, please, do tell or send me a PM.