I am not familiar with the "watch folder" utility and the "SendKeys" functionality in vbscript.
For me the OBS log is updated right away, but maybe there is some sort of buffering going on your system.
You can find a build of the plugin that let's you chose a file on the general tab to print the current status to a file here:
An automated scene switcher for OBS Studio. Contribute to WarmUpTill/SceneSwitcher development by creating an account on GitHub.
github.com
If you want more details on what I did you can check out the changes here:
github.com
Maybe that helps you in adding the functionality that you need :)
I am not sure yet if I will add this to the plugin officially as I do not think there is much demand for it - but maybe I am wrong here.