There is no loop setup currently; this is for a brand new desktop. So new, in fact, that I've been trapped in GPU unavailability hell. I'm going to do the planning for a CPU/GPU loop, but then put in a GPU that I have no interest in water cooling (probably an RX-580, because it's what I have lying around), and roll with it until I can actually buy a 6800 XT that's compatible with the kit's included GPU block.
Coincidentally, that's why I don't quite have a case picked out. I could re-use the case I have, or I could try to get a new one that actually has space for a fill port and a drain port built-in.
My current plan for the layout is is:
front-rad with the ports down
pump-reservoir near the front centered vertically, against the motherboard tray (with brackets)
CPU block in the usual spot
Vertical-mounted GPU
GPU -> CPU, CPU -> Fill Port -> Reservoir, Reservoir -> Radiator, Radiator -> Drain Port -> GPU
OK, so if I use a ball joint, instead of the Quantum Torque drain valve, I save $5 from the valve, and $14 from not needing the extender, at the expense of the ball valve not quite fitting in aesthetically (not quite the right metal, different design aesthetic). On the plus side, floating ball valve; maybe I don't need a dedicated drain port cut into the case itself, elegant as it would be to know for a fact the drain valve is at the lowest spot in the loop.
The kit includes a bottle designed for filling the reservoir directly; just unscrew the plug on the radiator, fill to below the hole, juggle the fluid, and presto, all set. As you can imagine, I was hoping for something slightly more elegant (like knowing for a fact that the fill port is always at the very top of the loop for easy filling), but maybe I'm over-engineering again.
The EK kit I linked to includes a flat res/pump, that already includes spots for a fill port and a drain port. Not sure it makes quite as much sense for me to use them in a case that can front-mount a 360mm radiator, but whatever.