I'm sure Porre's army is much larger than Dalton's group of cronies. Even though we didn't see Porre growing a military in CT, by CC they seemed to have reached some hefty proportions. We can safely assume that by the Fall of Guardia, Porre had either grown a large military, formed alliances, or hit some kind of technological growth, or a combination of those three possibilities. Regardless, they nailed Guardia. They nailed 'em hard. I agree that Dalton seemed to have some technological know-how...and I'm sure the technology he was accustomed to in Zeal surpassed 1000ad's by a good margin. With that technology, innovation, knowledge, and mindset, he probably brewed up a very formidable force that Guardia was under-prepared for.
Although, like some have pointed out, Dalton didn't necessarily create any of the technology he used...but he did oversee the construction, and that may have given him some upper hand...Perhaps with enough labor and a group of engineers, he could have given Porre a huge technological advantage.