It would help if you could be more descriptive.
1) When you say "blueprints," are you referring to the .pdo files that you open in Pepakura?
2) What type of armor are you trying to build? There are a number of files for shoulders for any number of types of armor. Are you doing ODST, MARK VI, MARK V, MARK IV...
If we can understand what you're actually referring to, we might be able to help. Otherwise, it's just a whole lot of this: