solar panels for grundfos?

Hi,

I am new here and looking for guidance on a water pumping system. We are pumping water for livestock with a grundfos 6 sqf pump using a generator and a IO 101 box and a CU 200. With the generator the CU 200 reads 450 - 490 watts with 126 volts AC going to the pump. My question is what kind of solar system would run this pump? Does the voltage of the panels make a difference? Would four 145 watt - 18 volt panels wired in series do about the same thing that three 185 watt - 24 volt panels? I know the watts aren't exactly the same but what I am getting at is, does the panel voltage matter as long as you get the same ending voltage? The well is 160 feet deep, we have 12 gauge wire down the well, and it pumps to a storage tank about another 160 feet higher but it takes a mile of pipe to get there. What I am wondering is the 72 volts enough or do we need more? To get more do we use lower wattage panels and more of them or does it matter? I understand the math va=w but do we need more volts in this application? Also what panels are recommended?

Thanks for any advice,
Reg