9/12/19 update: While putting the CPU and GPU almost at full load (GPU at full load and CPU around 75%), after one hour I was around 62-65 C on the CPU and 55-57 C on the GPU, with a fluid temp of 42 C. After watching more videos about fluid temp vs silicone temp, I conclude the Touchaqua temperature read out is fairly accurate, probably within 1-2 C. Temp readout of fluid matched the heat dissipation off the top radiator within less than 1 C. Used a laser to measure the heat coming off the radiator and got within 1 F temp on different parts of the radiator. Not perfect science, but at least I know the temp readout is fairly accurate.
This PC has gone through a LOT of changes since I first built it in January of 2019. Now it's housed in a Lian Li O11D Razer Edition with hard tube liquid cooling from EK Waterblocks and Bitspower. GPU temp at idle is around 27-32 C and the CPU temp (I have a rad in between each) is about 5-7 C higher than GPU. I did overclock but I've been having problems in some games so I set the ratio to auto.
If you go into cooling your CPU and GPU with one radiator, factor in about $300 or so in ONLY fittings! Get extenders, male to male adapters, 90 degree fittings that can rotate, etc. If you're scared about bending tubes, then spend more on fittings. Tight bends are very hard so having fittings can save you some tubing. This was my first attempt at hard tube water cooling and after a few bends I feel like I can do them pretty cleanly now, at least 90 degree bends. Just be patient and take your time when heating the tubes. I ended up spending more money in fittings (about $100 or so) and a second radiator because when overclocked at 5 ghz with one rad my idle temps were in the 40s for the cpu and mid to upper 30s on the GPU (at stock the CPU was about 7-10 C warmer than the GPU which was usually low 30s C).
If you don't overclock or have marathon gaming sessions, one 360 radiator up top will be fine. I do recommend you use fans in the vertical position if you air cool your GPU since it really helps with fresh air. 360 mm radiators DO NOT FIT FLUSH in this case. This is my ONLY complaint. It is advertised as being able to support up to three 360mm rads but if you want three then get the newly released O11 XL since it's taller and can accommodate the bottom fans and rad better. My pump on the distribution block front panel does not allow that large of a radiator in this case on the bottom, I probably can't even squeeze in any rads at the bottom because the USB 3 header sticks out so much. Because the radiator wouldn't fit flush, I couldn't fasten all of the screws in all of the fans. I ended up zip tying the top fan bottom right corner to the top right corner middle fan and there's no rattling or movement. The controller built in for the front panel on the case is why it won't fit flush. It's literally about 1 or 1.5mm too tall/thick and it sticks out just barely. This is legitimately my only complaint about the case is that clearance. WHEN USING THIS FRONT PANEL BLOCK AND PUMP YOU CANNOT MOUNT VERTICAL RADIATOR WITH OUTLET ON THE BOTTOM. It must be at the top since the pump would get in the way. With extenders you might be able to do a bottom mount if you have a 360 radiator and only use 2 fans at the top, but if you do that you might as well mount a 240 on the vertical instead.
The front panel distribution block's SP1 pump is a bit noisy, but you kinda block it out after awhile. I was concerned at first but when I watch videos or games I forget it's there until there's no sound playing.