Basic Hydraulic question

[WildBill]

Hello fellow tinkerers    Before I spend countless hours with the latest idea I've been thinking about, I was hoping to draw on some collective wisdom as I know several here have much knowledge and experience in the area of hydraulics. In my example below, I was wondering what the various outcomes will be with regard to the different hookup locations. Some basic parameters: The cylinder holds 1 gallon of fluid, and each tank holds 5 gallons and is open top. Now, since fluid try's to seek its own level, My assumption would be: With tank C connected, Pressure applied to the bottom of the ram would need to be 14.5 lb (atmospheric) + 8lb (fluid in the cyl) + 2 lb ( weight of ram and piston) + maybe 1/2 lb (weight of water column in upper discharge pipe.) = 25 lbs just to push the water out of the discharge.
       Since tank B is level with the cylinder top, I would assume the same numbers.
       But tank A, since you now have 40 lbs of fluid above the cylinder, My assumption would be that you would have 14.5 lbs pushing against the piston from the weight of atmosphere on the tank, so you would only need to apply approx 11 lbs to push water out. Am I thinking correctly? or did I miss something? Any help in understanding this would be greatly appreciated.

                                     Thanks, Bill

[onthecuttingedge2005]

you would need to give measurements to be precise, here is some formula that may help you figure it out.