I'm pretty new to this stuff, but from what I gather, you might be better off going a different route with the pumps and res. With that res, it looks like a lot of the loop pressure generated by the first pump will be lost as turbulence in the second part of the res. I would recommend going with a dedicated res and dual pump top that would direct the outlet flow from the first pump into the inlet of the second pump. Something like this:
Like I said, I'm new to this, so I could be wrong. But it just seems like it makes more sense to me.