How to change proxy on my webdriver multiple times on a single session?

I am working on a bot. I want the bot to change the proxy of the webdriver every 50 searches. I have an API that requests the proxy and the socket, i store those variables and so far i have been using firefox profiles to set it up but that doesnt work very well.

So given the fact that i already have a viable source of proxies and ports, can you tell me any way i can change the proxy without crashing the webdriver and doing it on a single session?

Previous attempts:

I tried setting up a firefox profile this way:

regions = {
    'US': '', #USA is the default server
    'Australia': #json response through the api,
    'Canada': #json response through the api,
    'France': #json response through the api,
    'Germany': #json response through the api,
    'UK': #json request response the api
}    
for region in regions:
        fp = webdriver.FirefoxProfile()
        if(regions[region] != ''):
            fp.set_preference("network.proxy.type", 1)
            fp.set_preference("network.proxy.socks", regions[region])
            fp.set_preference("network.proxy.socks_port", port)

This caused me some problems and i had to start a new session each time i wanted to swap a proxy. So i tried to change the proxy through the Firefox options (options - general - connection settings) but turns out the popup that appears on the screen after clicking the connection settings button is not accessible through selenium or javascript (xul file).

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