catalina yachts did not supply sails for the early boats and perhaps not until the later MK II model. certainly they do today. Most MK I and II owners purchased separate sails.
Sails depend on where you sail. Light air calls for 155 and full mains. medium needs a 135 and heavy areas can max out with 110s and flat mains. A 100 jib and main reefs is useful in vitrually all areas for the gusty spring and fall seasons. and of course there are light , med and heavy chutes to choose from.
BTW suggest you switch to catalina30@ yahoo.com for much more advice on C30.
Max Munger, IC30/309 Tech Editor