IMG 1724PaulK

Why are you replacing the mast and boom? They are generally considered fairly indestructible in normal use. New spars for a boat that was last built in 1983 will be mighty pricey.  If you buy another used Mirage for its mast & boom, how do you know they’re any better than what you already have?  Replacing rigging is more common. For that you can send your old shrouds and stays to a rigger or an outfit like West Marine and they will make a new set for you that matches.  No need for you to measure anything – they’ll take care of it.