WakeWorld - Need help designing a custom ballast system

Taken from the other site: I have looked at a bunch of posts regarding custom ballast systems & it is obvious there are many ways to skin a cat. I am thinking of a 4 bag set up for my Centurion. My main design goals are ease of use, speed for fill & drain as well as low cost. I have four Skylon fat buddies that I will use to start with b/c they are just sitting around collecting dust. I am thinking one in each locker out back & one under each front seat. I realize I won't be able to fill the front ones to capacity & may eventually have to go with the fly high under seat sack. The plan is to run 4 Tsunami 1220 pumps for fill & four Tsunami 800's to drain. I plan on running a scupper in the hull instead of the factory thru hull fitting from my center ballast so I can fill while idling through my no wake zone. I will run a manual ball valve off the intake to shut down for emergencies. I would like to run all four bags off individual switches so I can fill & drain each bag independently. Will one pick up in the hull be enough to supply all four pumps? I will need to create a manifold for the single inlet line to split into four inlets, this would be the best place to mount the inlet pumps I think? Can I use less than four pumps, would it be quick enough or do I need one pump per bag to fill? I also imagine I will need some check valves in the vent/empty lines to prevent draining? Can I run two pumps per bag with one pump being fed from the inlet in the center or rear of the boat & then one pump with a line out to a thru hull that would act as a drain & vent? Better yet can I run a pump or two on the manifold from the inlet then run a pump per bag to empty reducing my cost even more? Thanks for any help or suggestions.