Nice build! In fact, such a good build, I built a very similar too. firstname.lastname@example.org (1.25v), RTX2080, AX1200i, 2x970evo 500gb, 3x120 custom loop, etc.
As for questions about pressure/heat, I may be able to add some info. My last case was a 850D, with tons of negative pressure (3 rad fans on top out, rear fan out, and a 2 fans in the case kinda recirculating, one the HD bays, the other the lower compartment up to the main). The 570 I have front and top fans (5x120) going in, with the rear fan out, creating positive pressure. Also went from top RAD mount (out) to front mount (in).
Temps are amazing on the 9900k, gaming in the 40-50c range, max temps when doing email@example.com (h264) is in the 70s, slightly lower than my delidded firstname.lastname@example.org, but at a full 0.1v lower. Gpu temp went from about 55 to 58 playing the same game since I am pushing air down past the card instead of up, and the slightly warmer air temp coming from my radiator (RAD reads the same as room temp when testing with a laser thermometer).
Main: I9-9900K@5.1Ghz 1.25v/16GB DDR4-3600 15-15-15-35/RTX2080/500gb 970evox2/Custom Waterloop/Corsair 570x/AX1200i
Server: I7-7700K@5.0Ghz 1.35v/16GB DDR4-3600 16-16-16-36/GTX1050ti/500gb 960evo/WD RED 6TBx2/Hyper212LED/Corsair 800d/RM850