With your overclock on the cpu and 2xgpu, it's about 1000w according to the evga psu calculator. Add 10-20w for pump... and ssd heat load is hard to calculate with the calculator. So, we will call it 1050w load.
What water delta are you looking at staying around? For a relatively quiet build at 10c water delta, you're looking at roughly 100w/120mm^2 surface area with 1000-1100rpm fans. So, at your overclock, you would need about 10x120^2 surface area calculating only the radiators releasing heat. Heat is released through tree blocks, tubing and fittings as well inside the case, but considerably less than radiators. We can estimate that 80% of heat will release through the radiators. So, designing the radiator surface area for about 850w would mean that roughly 8 or 9x 120^2 would give you the cooling you are looking for.
You could use 2x480 if silence wasn't really a priority or didn't mind slightly higher water delta at full loads, but 2x360 will be a little low for your heat load and search of silence.
I personally design my systems to have as much surface area as I can... I usually don't reduce the amount of heat that the blocks/tubing/fittings release, and look to exceed the wattage at load with radiator dissipation wattage.
What case are you planning to use? If you can fit more than 2x480, I would. Also, if your case can use 140mm wide radiators, you would be able to increase surface area if you cannot go with a longer radiator.
I personally prefer single serial loops, gpus in parallel, but in series on the loop. With separate loops you always lose out on potential cooling performance from radiators with less load. With a separate loop, you may need something like 2x360 for the gpus and a 360 for the cpu.
As far as pumping power, you could run off one good D5 or DDC pump so long as your blocks and radiators are not very restrictive. You can do the math, but in general, gpu in parallel reduce restriction and most cpu blocks are much less restrictive than what trey used to be. Thicker radiators have low restriction, and using fewer larger radiators are less restrictive than more smaller ones. One variable is the restriction of the ssd blocks... You could add another pump in series for redundancy and more flow, but I don't think it is entirely necessary unless your loop is using the new alpha cool block and GTS rads.