I would stay away from the 1260 if I were you, as it's not a great choice for watercooling. Its PQ curve is very flat (due to a high maximum flow rate and a comparitively low shut off head), and as a result you'll most certainly be operating the pump below its peak efficiency. pHaestus has done a great job of summarizing a variety of pumps
here, which you can use to help make your decision (and if you can't, feel free to ask someone here how to do so).