Quote:
I also assume that the designation in the list of proxies on my machine that follows the "/" is the port name, and that I'd use "80" for "HTTP" or "443" for "HTTPS", and so on.
True?
What is "your machine"? What O/S is it? What command or file are you looking at?
Some free proxies out there use the standard port 80 for http whilst others use port 8080. Normal port for https is indeed 443.
You need to get such information from the proxy provider to know how to configure it.