HTTPS and wptserve

What are the current practices for using wptserve for https testing?
I was only able to find very limited documentation for some command
line options.

http://wptserve.readthedocs.org/en/latest/server.html?highlight=certificate

Do I have to run multiple instances of wptserve?  (secure and not?)

What class do I specify to get a secure server process?

What format does the "certificate" take?  (Apache, for example, puts
the certificate chain and public keys in different places)

Can I put this in a config file somewhere?  Where?  Is there an
example?  (the web-platform-tests README.md mentions "config.json" but
I don't see that anywhere in my cloned repo)

thanks,

Brad