I am unqualified to answer your first 2 questions, but as far as hyd. cooling, the 737 uses two identical "radiators" one in each fuel tank for hyd SYSTEM not pump cooling. The fuel requirements should be the same for each system as the radiators are in the same place in their respective tanks.One addition point is that the left tank contains the system A cooler and the right tank the system B cooler. If you ever experience fuel migration, note the hyd. quantity, you could be "making" fuel. Not a likely scenario, but certainly not impossible.