Gale never used the lab although I think the lab was originally built for Gale. When Gus brought Walter there the first time, everything was brand new and completely unwrapped. Walter was amazed at the items Gus had purchased and the lab he had set up. Gus mentioned how much he needed to make in order to be profitable. Walter turned him down but changed his mind a few days later because of Jesse - making him a half-partner.
The only thing Gale made was coffee and Walter, in order to get Gus out and Jesse in was overly critical of Gale and insinuated that he had made mistakes.
Gus spent 25 years trying to get revenge on the cartel, but I'm almost certain the cartel provided all of the meth before Walt/Gale came along. This is why he paid for Gale's education - he was hoping he could become independent by training him and plotting his revenge. Gale may have had a smaller lab elsewhere but he did not use that lab.
Gale also mentioned something to Gus about him being a perfectionist and that his meth would never be good enough for Gus. Gale was also pressured towards the end of S4 to quickly learn Walt's formula so he could kill Walter (or in case he died from cancer).