Hey there,
If you were wanting 2 x 240mm radiators and not fussed on looks (assuming so given you are considering flipping the case), you can run a 240mm slim radiator in the bottom with 2 slim noctua fans under the GPU, provided the GPU block you use is a single slot (most are).
Alternatively you can get taller feet for the case and mount some fans under the case and dremel the fan slots in the bottom for better flow (though this may have an effect on the case rigidity, but if the radiator is mounted properly in the bottom that will assist with some of that).
This would free up space between the radiator and GPU also, which will help.
In addition you can then side mount another 240mm radiator.
The only consideration there is what pump/res you choose. There are some alphacool cpu blocks that include pumps and there are reservoirs you can buy specifically for the ncase which mount to the rear 92mm fan bracket.
Personally I am currently using a glass side with a 92mm rear rad and 240 bottom rad with the fans squashed between the GPU and rad. My temps are around 65c on the cpu and 55-60 on the gpu while gaming for extended periods. This is with a delidded 8700k at 5ghz and a 1080ti at 2012mhz.
Synthetic tests can get my CPU up around 70 degree's or closer to 76 if stressing the CPU and GPU at the same time.
Unfortunately I think there are better results to be had with air in the ncase m1, or with a 240mm aio for the CPU and something like a Accelero3 for the GPU, but it sure looks nice with a custom loop.
My next trick will be some taller feet and bottom mounting those fans to try get a bit more flow through the rad and up and out the top of the case and putting an exhaust fan in the top to try get rid of some of the hot air in the case as all my fans are currently on intake as I found this to net the best temps.
