They will help tremendously if the operator cooperates.  They will do approximately nothing if the operator does not. 

In order to help, the weight has to be sitting on the accumulator.  If you just raise the head until the pump squeals then the accumulator will be full of oil and it won't do much good.  You need to raise the head until it is up and then stop before the pressure starts to climb.  

Accumulator would just be attached to a tee in the line between the cylinders and their valve.