Regulating 552

Yes, CW will slow the watch down. How much each turn slows it down depends a bit on how the regulating pins are set-up. If you are using a timing machine (highly recommended) you will be able to see how mch fairly quickly. If you don’t have a machine, I would try turning it one full turn and see how you go.

Note that if the watch hasn’t been serviced recently, trying to regulate it may be a fruitless exercise...

Considering a watch that kept excellent time when it was in excellent condition, accuracy can change as condition deteriorates over time. Moving the regulator was never meant to compensate for the factors involved in deteriorating condition.