How am i doing...?

Eh up!
3rd proper grow here, Dutch Passion Strawberry Cough in DWC day 38. As you can see, my attempt at keeping a nice even canopy near the scrog worked out really well!!
Im a sativa guy so this comes with the territory i guess. I dunno, i just have a bad feeling things are gonna go tits up at some point. What worries me is that there is zero air flow, no fresh air coming in no hot air getting sucked out. After 12 hours zip up on dark its pretty darned humid in there, 70-80%. Tent is unzipped lights on so that levels out.
Everything ok in dwc bucket ph very stable 6 - 6.5 ppm stable around 900.
Have seen one or two bugs flying about but seems very isolated.
I think im good right...?
Cheers!

I'm about as far in as you are, my 3rd proper grow, although I've only run hybrids, so they stay smaller. Damn that's a leggy lady! But you're buds are looking good. I've a northern lights that is about a week and a half in flower, she has gone a bit wild but I'll clean that up in about another week and a half. The gallon milk jug is just for reference.

I would look into an inline fan. My 4" only set me back about 20usd. That humidity has got 12 hours to hang around your buds I would be very concerned about bud rot. Even a box fan is better than nothing.