Since the oil pressure sensor is upstream of the cooler and filter, you won't see a pressure drop on the regular gauge. I assume you plan to set the coolers up in series, with the oil going through one and then going to the second one. There will be a pressure drop, but I have no idea how much. Your best bet would be to talk to a knowledgeable person at Jagg. Have you figured out how you would run the lines to each cooler? If you care how things look, you have to take all those lines into account, not just the coolers.
You might want to consider the ten row Jagg low mount with or without a cooling fan; they make it both ways.
Jerry