Re: preserve deleted remote files to recycle bin
You can do both, registry and INI file.
See https://winscp.net/eng/docs/custom_distribution
See https://winscp.net/eng/docs/custom_distribution
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
Every WinSCP settings is saved to either registry or INI file (depending on your preferences).
Why do you want to set it via registry rather than via GUI? What are trying to achieve, exactly?