Still to this day, most wargaming rules broadly classify the Spanish into the traditional three categories: Lusitanians (skirmishy), Iberians (loose & flexible), and Celt-Iberians (wild & hairy). Other ethnicities get lumped into those three. If there are other variations in published ancients rules, I've missed them so far.
The more I read about Spanish tactics and military history before subjugation to Rome, the more I doubt this is a complete enough picture. The Spanish peninsula was inhabited by multiple cultures that were only vaguely related, and we already know the major differences listed above. I bet there were quite a few minor but important differences as well. When I was researching this topic for a Punic Wars Spanish campaign, I decided the Edetani, Turdetani, Bastetani, Contestani, Oretani, etc. may have had yet other approaches to tactics that just aren't well documented (at least not right now – how many documents disappeared in the last 2200 years?). I'm inclined give the peoples in more rugged areas of the peninsula more skirmishers, looser massed formations and less staying power; and the more sedentary peoples living in cities across the south more massed troops and cavalry.
I'm also inclined to vary the staying power of Spanish troops based on their relationship to the alliance they fight for. There are lots of stories of Spanish doggedly resisting to the last man, and plenty of other stories saying they broke and ran early. I suspect this probably comes down to what they were fighting for. The troops fighting for their own freedom or to defeat an invader should fight harder, the troops fighting because they're conscripted or recruited for money should fight less, uh, doggedly.
I've encountered a published revision (can't find it again…) that claimed the Spanish scutarii must have fought more like the Roman legionaries because their panoply and tactics were superficially similar (shower of javelins before contact, fighting in loose formations with short swords behind big shields). They clearly didn't fight as well as the Romans in pitched battles, so I'm not sure re-rating scutarii the same as legionaries is warranted. It's possible some Spanish city-states might have had a similar level of organization, drill and training as Roman infantry, but I doubt it was many.
- Ix