The coincidence of similar or even identical names within the same state still presents a problem. In order to minimize guessing as much as possible, it's useful to know where the man in question lived, his age and occupation. That allows us to filter out unlikely candidates due to residence, age or occupation. We can then attempt to match individuals to soldiers from specific companies raised in the right counties. For instance, your knowledge of the 15th South Carolina Regiment makes it possible to recognize which districts are likely to have contributed officers and men to this comannd and which are not.