Hey Labman, you can always harvest in stages, as we were recently discussing elsewhere on the forum. You know, it never hurts a girl in flower to give her a 48-hour flush every few weeks or so; they love the brief respite from the nutes, and you will often see invigoration after you put them back on their nutes. I'm not sure how many more weeks your big colas are gonna need; maybe someone else who knows the strain will chime in.
But I am in week 14 of flower with a big sativa girl, and I can see that the buds down lower on the plant are beginning to ripen, while the buds at the top are still putting out new pistils. I am sure that I'll be taking parts of her down in stages.
So you could do a mini-flush (and I hope as she winds down, that you are winding down on the nutes, so you have less salt buildup to worry about...) and harvest what's ready to be harvested.
