Hammi, I found a bug because of your https question. Github is now updated with a fix. passing proxy=True makes it look for proxies.txt in the current folder. you can pass an alternative filename, a list of proxies line seperated or a python list of proxies instead, it's pretty flexible. Anyways, my https testing:
>>> web.grab('https://ipcheckit.com/',xpath=True,proxy=True).xpath('//b/text()')
(one of my private proxies)
>>> web.grab('https://ipcheckit.com/',xpath=True).xpath('//b/text()')
(my home ip)
>>> web.grab('http://ipcheckit.com/',xpath=True,proxy=True).xpath('//b/text()')
(another of my private proxies)
>>> web.grab('http://ipcheckit.com/',xpath=True).xpath('//b/text()')
(again, my home ip)
so it is pulling proxies from proxies.txt, when told to, and correctly loading a https and non-https page.
This stuff really shines when doing 500 requests at once with gevent
Edit: It just clicked what you meant by authentication, yes it should work.