Removing the header tank function and its contribution to W&B requires that you think about all the consequences.  Placing the battery and hydro pump and other items forward is definitely a maintenance positive.  Consider that 9 gal of fuel weighs about 54 pounds and that the movement of items from the back to the front may adequately compensate for that loss.  Compute the weight and balance change.

 

The more important requirement for low-wing fed fuel systems is the inboard slosh chamber that should be built into each wing.  This protects the engine fuel supply from being interrupted during low fuel conditions such as uncoordinated maneuvers, turbulence, etc.  It also may increase the minimum fuel requirement in the wing used for takeoff and landing.  This should be tested by tilting the pitch of the plane (or wings) to see how much fuel is needed to keep the intake from becoming unported.  If your wings are already closed without the slosh bays, you may want to consider building a small header tank (maybe 3 or four gallons) and still move some equipment forward.