Ian, to answer some q's
I'm actually the one that found the spring fix on the solenoids so yes the springs are removed.

I did not change the diameter of the pump discharge hose. The clear just looks bigger.

The original manifold had water fed on one side, and the new one has a pump fed to each side.

The unused port on the center sac is correct. When the center sack is full it overflows into the bow sack. Then when I want to empty it I just turn on the bow discharge pump. Just like you would any other sack in your boat.

The bow discharge pump is plumbed up to the where the center sac discharges out through a thru-hull fitting. I have not bought the fitting or drilled the hole to the new fitting/plumbing.

Make sense?