i know there's threads out there for different methods on this but the question I'd like to know is could i get away with just using the marks on the rear axle section or do i have to use the string or laser methods. the reason i need to align it is just so i can do the 14t sprocket swap and so i have to tighten the chain.

 

The marks are typically close enough. Next level would be an axle measurement to a known parallel on the bike such as swing arm pivot or the like. Usually pretty easy to do also.