Fractal Design R6 Type C Waterloop & Airflow

[BliitzTheFox]

I am looking to move my current system into a smaller case and apply water cooling. Since this if my first time with custom water cooling I'd like to make sure i'm not doing anything obviously wrong.
My current system
Graphite Serie 780T White Full-Tower 
Intel Core i7-7820X Delidded

Asus Rog Strix x299-e gaming
Asus Rog Strix 1080 ti x2 SLI
Evga 1000w G3 Gold
16gb Memory 4x4gb
Noctua DH-15s 
A total fan count of
2 x NF-A12x25 PWM

5 x NF-A14 PWM 

Planned System Changes & purchases (prices at time of writing)
Fractal Design Define R6 USB-C White TG $187.42
LINKUP 30 cm shielded  PCIe Riser $39.96

2 x Eathtek 120mm Lon flexible SLI Bridge $8.75ea

EKWB EK-KIT X360 Complete triple 120mm Liquid Cooling Kit $419
EK-KIT includes
EK-Supremacy Evo
EK-CoolStream XE 360
EK-Vardar F4120ER
EK-DDC 3.2 PWM Elite
EK-CryoFuel
EK-RES X3 150
various tubing and fittings.
Budget for upgrade around $700 but flexible.
This will be my first liquid cooling loop. I decided to forgo Aios as none would have been good enough to out match my Noctua NH-D15s (with two fans). The goal is to achieve quiet overclocking performance on the delidded 7820x and I realize a 60mm thick 360mm radiator may seem like overkill, but I want to eventually expand the loop to include both 1080 tis and/or a slim 420mm radiator mounted to the top. I realize that the DDC pump is not going to be as quiet as a D5 but I figure this is something I can change latter if it is bothering me and the kit is cheap enough that buying everything separate isn't an option.
I currently plan my setup in the follow picture and foresee a couple problems.

(RGB not shown)
The goal in mounting the Graphics Cards is to have one vertical and the other horizontal to give each one it's own temperature zone and room to breath while still achieving HB SLI by tricking the card into thinking two flex SLI connectors are actually HB bridges from covering the center grounding pin detailed here, see comments. This still poses other mounting questions. Will the power connectors interfere with each other? Will the graphics card's air coolers overlap?

The second question is a matter of airflow. Normally in a case your intake would be low and your exhaust high because warm air rises; however, I'm not sure that approach would be ideal here as all the intake air from the front would not only be warmed up by the radiator right away, but then be obstructed by the reservoir before finally feeding the 1080 tis.
Perhaps it would be better to reverse the direction by using the top and rear 140mm fans as intakes and exhaust on the radiator. I'd be interested in knowing what people suggest for best radiator, vrm, and gpu airflow.

Also somewhere I have to mount a 3.5in hard drive after removing all those bays, but that's not a big issue and i'm sure I can rig something out.