You can beat yourself up about pressure drops and flowrates etc until your sanity leaks out your ears. Truth is that you're only going to get a realistic idea of how a loop performs by building it and seeing what happens. Maybe you'll see a difference by increasing flow if you don't really have enough rads to cope....but honestly I'd be surprised if you see as much as two degrees difference with varying flow rates. Try it, see for yourself the difference - that's the beauty of the Aquaero; it lets you put all your paranoia to rest.
I've got a simple loop with GPU, CPU, Rad and Res. It takes two 18W DDCs to get as high as a gallon an hour. Is it necessary? No. Only got them for the redundancy and the overkill. Only need them at full power if trying to run a fountain!
Similarly, you may look at temperature sensors at different points in the loop because it's going to be colder aferathe rads, right? Nope. It all reached an equilibrium and any differences are below the level of inaccuracy of the sensors you'll be using (up to 3°C isn't unexpected).