do you know if the watch has been serviced recently? with vintage watches, i would typically send this off to be serviced by ziggy immediately after i received it -- for vintage watches, you typically never know how long it has been since the last servicing (or even more important, the quality of service it received).
if you must wear the watch in the meantime, i'd carefully wind the watch (read: slowly) until you feel tension in the mainspring and it won't wind anymore. you'll be able to feel the spring getting tighter (ie. close to fully wound) based on the growing pressure it takes in each subsequent turn of the crown to wind the watch.
hope this helps
deltatahoe
ps, let's see some pictures