Single Radiator or Dual Radiator?

Well I'm still working and saving up my money check by check to get enough to completely rebuild my computer but I'm still doing WC research. So here is my question, first I know that having more than one radiator does hurt the flow and a single radiator/heatercore is best for flow but anyway to move on. So when I do get a new PC, I will most likely get the CM stacker. Now here are my questions. It happens to be that unless I can mount a radiator on that 3 in 1 thing up front the only place I can mount a 120mm radiator is on the back exhaust around the middle on the back of the case. So which of these options is best and which ones are possible.

Can you mount radiators on this all in 1 device? These will be black ice since I decided against a heatercore just because of simplicity of rads made for water cooling. If I could mount it on these 3 in 1 devices, would it be worth the $150-200 for a triple 120mm and 2 extra all in 1 devices?

Would a single 120mm radiator on the back exhaust be better than a 120mm rad there and another 80mm rad at the top exhaust? Would the flow loss be too much to counter the extra cooling the water would get?

Third, what "silent" fans would be good for these setups? I'm more concerned with trying to keep the PC almost silent while getting decent cooling for mild OCing. I've heard good things about panaflow. I currently have some 80mm vantec stealths but they seem to be a little on the whiny side causing a lot of noise.

your going to want to have any rad you may buy be fed with air coming from OUTSIDE the case.
A double 120mm radiator is always better as it will be able dissipate more heat than a single 120mm rad.
It is more rsetrictive though, so in order to even out the differences maybe consider a single pass double 120mm rad.
good luck researching