true cantilever rear suspension (2:1 ratio help!)

whats up, i'm building a true cantilever rear suspension on my mazda (not the bags on 4 link bars style lever), and i have a question about the ratio. i want to setup a 2:1 ratio, i have the basic plan of how i am going to make everything, but my question is how do i make a 2:1 ratio? do i make the pivot plates twice the size of the bag infalted? or twice the size of the bag deflated? or do i make the actuator bar (rod) twice the size of the bag inflated, or deflated? i just basically need to know how a 2:1 ratio would be set up, any help would be appreciated, thanks alot.