Just as a starting point, i would like some opinions on what would be sufficient for my dual SLi GTX 970 water cooling.
 
Pump, reservoir, tubing, fittings and water block are all self explanatory. As is the fans that i would choose. 
 
But my question is - the one thing i have not been able to figure out - is what size radiator for my purposes. 
 
I wont be overclocking my GPU's by that much. Much later in their life i will likely go further and further, but for the time being (for the next year anyway) small overclocks is as far as i will go. I have a CPU water cooler in its own setup so this will be a dedicated GPU water cooling ''loop'' i think its called. I like things being separate and dedicated so what radiator i choose will be dedicated solely to the dual GTX 970's. I know all too well people love the idea of an all in one water cooling solution, CPU and GPU(s), but i personally like to keep things in my case separate. 
 
Single seems too small for dual SLi even if i am not overclocking it all that much and triple seems a little overkill for the same reason. Looks have zero meaning for me, so i am likely to choose completely black tubing as my case is built 100% for function and 0% for looks. Nothing in it is for looks - everything must have a function. So i personally dont care what the radiator looks like, as i wont be staring at it with glee :P. 
 
I just need a starting point, not a shopping list!

First off, it is (or will be eventually when i can buy the second one) a dual SLi card setup so that means two 970's. I am not sure if that makes a difference. 
 
And whilst i DO in fact have a triple radiator slot on the top of the case, there just isnt enough room to house it unless i not used one of the 3 fan positions. Everything else in the case, the motherboard, CPU cooling and the heatsinks soldered onto the motherboard prevent a third fan from being added to the top rear of the case in addition to a radiator. Fan or radiator by itself, there is enough room, but not both. 
 
So in theory i could have a 3 slot radiator (360), but with the fan position closest to the top rear being empty (making 3 slots pointless) or a dual fan radiator (240). I dont know, would it be pointless having a 360 with only 2 fans attached?
 
I do appreciate your help on this nonetheless. 
 
Some personal issues are preventing me from progressing with my build for at least a few weeks so i have heaps of time to deliberate on this. :)

I will be overclocking the cards.. but not remotely close to maximum. On a scale from 1 to 10, with 10 being on the knifes edge, i would never go above 5.

EVGATech_TimP
Hello mouseno4,
 
If that is the case, you should be fine with a dual 240 radiator. However, if you have the budget, triple 360 radiator would not be a bad idea. :)

Budget is never the issue. If i had the space, i would go 360. 
 
Put it this way, i just opened my case up right now to measure the clearance from my already installed 140mm top rear case fan. 
 
34mm from the fan housing to everything else. The absolute thinnest radiator that i know of, is 38mm. 
 
The best i could do is REDUCE the top rear fan size considerably to eliminate the clearance problem. I would have 3 fans on the radiator yes, but only two of them would be 120mm, where as the top rear would be... much smaller so the clearance from the motherboard would not be an issue. Possibly 92mm or less.

I have not been able figure out why SLI bridges exist in the first place when the hot liquid from the first in line gets transferred to the next card, effectively lowering the heat dissipation for every card beyond the first.

And why would you have the flow of cold water go through the pump BACK to the radiator? Seems a bit pointless to me as the radiator is there to cool the water. Sending cold water back to it BEFORE going to a GPU or CPU seems counterproductive.

Back on topic, i would use a 360 as that would give me the simple biggest head room for any overclocking whatsoever. I could go as high as my card would go, with a 3 slot radiator, it would make it possible. 
 
But alas, the problem isnt price, design aesthetics or whether i would simply want 3. It has to do with the Enthoo Pro case coupled with the Asus z97 Deluxe and its motherboard heatsinks. To put it bluntly, it just wont fit a 3 slot radiator with 3 fans. At best i could have a 3 slot radiator but only 2 fans on it - middle and front with the rear one empty. I personally think that would be a complete waste of time having a 360 radiator with only 2 fans.