Quote:
Revised my proxy list and increased timeout to 300 seconds (it was on 120). Still getting endless attempts.

A proxy could be basically "live", that is, able to load a random site online (and we check that), but at the same time blacklisted by Google - and that we can not really check unless we start checking rankings. So in your case you could try to find the best human emulation/amount of simultaneous tasks ratio and not use the free proxies.