Mike,
For most carburated setups, you should "normally" need only one pump.I'm going to use F.I. Most are using dual pumps and tubing with awitch over setups, but I get lost in all the switchover stuff(not to mention the cost), so I am considering linking the two tanks like Lotus does, put a one way valve between them toward one of the tanks that will have a low pressure pump to the swirl pot. From the pot to one high pressure pump to the fuel rails. A regulator, then return line to the swirl pot, and an overflow to the unpumped tank. It may not sound simple but it should work. It keeps the fuel moving in one direction, keeps the fuel flowing to the high pressure pump, and it does away with all that duplication in plumbing, pumps,electronics and switches.
Bill