Depends on your version of Windows. In general, you can't set the TCP Receive Window with newer versions (Windows 7/8/10). With dialup, you may want...
I would pull out my phone and take a picture of these people while they're standing there, it might have some psychological impact on them, and then...
The majority of important settings are not adapter-specific, so yes, it will apply them to your system in general. The few adapter-specific settings...