It is also worth cheching the thickness of the new bridge insert. Older guitars tend to have slightly thicker inserts and so will aLter the parameters for string length. I make my own from bone blanks (for a 1987 Martin D18 dreadnought, usualy played in DADGAD).
On a general note, always try to get advice from someone who plays in a similar style to youself as they are likely to have the same problems.