How long they been in 12/12 for? I'd say you have more than a week to go.
You shouldn't harvest while there are any healthy white pistils, they will eventually brown all over and recede into the bract. Each individual floret should get really fat at that point.
I'm at day 36 and I have a (C99 x Diesel, head high) plant that looks just like yours, maybe 30-40% pistils getting golden. The day-to-day changes are slower, but you can tell that the flowers are getting bigger. You wouldn't want to harvest before hitting that specific ripening phase where they all get big.
Then again, I'm going on hearsay and reading, patience is the most important aspect for the end of flowering. I've read many times "when you think it's done, let it go another week".