I’d recommend skipping the stress of having the exact time and go straight to enjoying your vintage watch. Chart the accuracy every so often so you can keep an eye on things.
You might be able to back hack it. That is when it only has a few turns of wind ie a very low reserve, you may be able to stop the second hand with a little back pressure in the time setting crown position. This works on a lot of man wind watches but takes a bit of practice. Obv once the time is correctly set you wind on more reserve.