Man, I'm just now finishing up chopping/harvesting my first grow, and I ran into several similar symptoms as you as far as some buds being slightly premature at week 8.
In my experience, the best thing you can do for your plants is give them enough time. I had pH problems in the beginning of flower that really fucked my bud growth up and cost me some yield. A lot of the colas didn't quite fill out even after letting 8 week strains run 9 to 10 weeks. BUT, even tho they didn't quite fill out, giving them the extra time definitely helped them develop fully.
I think your plants are looking pretty good, and I don't think they need 3-4 more weeks. The calyxes look like they are swelling nicely. I wouldn't judge it by the hairs either, go by the calyxes and the trichs. If you start flushing now I'd say she'll be ready in 2 weeks. It can suptise you how much the buds plump up in that last little bit, but don't expect the colas to completely gill out if they havent by now.
Good luck bro, I would love to run that strain.