I used GV for about a month. I didn't have thrush, but they thought I might have another type of bacterial infection in my breast. My infection cleared up within a few weeks. DD never got thrush.
It was a little messy. I just used a Q-tip to swab it on right before breastfeeding. I never did swab my DD's mouth directly with it because she got a healthy coating of it just from breastfeeding immediately after I swabbed it on. I always wore breastpads, so my clothes and bras never got stained. I just made sure to wipe up any drops from DD's face and my breasts immediately after breastfeeding.
I'd say the purple mouth, tongue, and spots on DD's cheek cleared up after just a couple of weeks from when I stopped using GV. It took my breasts a couple of weeks longer to no longer be purple.
DD is also a thumbsucker so her thumbs were purple the whole time too.
I'd say to go for it since you know the Diflucan doesn't work for you. It doesn't hurt you or baby. My Lactation Consultant recommended that I try it BEFORE I try the Diflucan since she knew I am a "try the natural way first Mom".
I found my GV through Amazon.com, but I've heard you can find it at Walmart in the bandaid/first aid section. My Walmart was totally out the day I went, so I ordered it from Amazon and got it two days later.
Dang! If you had posted this just one week earlier, I could have sent you a brand new bottle that I never used for free! But I gave it away already. I only ended up using about half a bottle for the whole month I used it, so definitely just buy the smallest bottle you can find.