Got some time last night so I worked on this a bit. Temporarily using 2 plank of wood for a make-shfit frame for the rig.
Just another in-between-step to finalize callings, and fits.
But this rig looks pretty damn compact:
For size reference, the bottom piece of wood is roughly 8.5"x12". The height is also roughly around ~8". So if we can shortened the distance a bit (about ~1"), the internal volume could be 8.5 x 8.5 x 11".
I'm actually quite please of how cool it looks in its "open form", lol. And this rig will probably stay this way for a bit until I find some more time to work on a case (not sure if that's even coming at this point as I've been consistently been taking builds apart every time I come up with an idea).
I have also tested this rig as a standing up orientation. From my experience, the numbers aren't better. I thought it should if it just one flow of air from bottom and exist top. But that wasn't the case, I still have been getting consistently better results when it's lay horizontally with the two fan blowing opposite direction (where the two air flow meets in the middle and exist from top). I think this has to do with the fan blowing air directly into the bigger of the two heatsink and this cools the CPU and GPU separately at the same time. Whereas a single direction airflow would means that either the CPU or GPU gets priority and the one sitting at the end of the air flow gets the hotter air blown through the heatsink.
With the two air flow meeting in the middle, both the GPU and CPU are being cooled equally. I think this is important as the 9900k runs VERY hot and needs just as much attention as a full load GPU. When testing the single-flow standing orientation, I remember there were a few instances where my 5Ghz OC on the 9900k won't hold up as there were spikes in temp under heavy gaming load.
Current spec testing: 122% Power limit 2080 ti (hitting 350W in-game). OC 5Ghz all-core 5Ghz i9-9900K. Temps for the CPU jumps around so it's hard to quanitfy a number, but somewhere between 60-70+ under various gaming load. The GPU under 350W runs around ~65 and can spike a bit above 70+ (I think happens when the CPU hits a heavier load and the heat itself gets applied to the nearby GPU's heat-sink).
Pretty happy with this so far. Sorry for the long and perhaps incoherent stream of thoughts
Just figure those who are interested find the info interesting.