@confused - you have posted another question (asking about the same) - and there I gave you already some answers. Look into the tables I have recommended - and you will see that all 4 stages must have the same pole frequency (which for the Butterworth case are identical to the cut-off frequencies). However, the pole-Q values are different. If the gain values of each stage are the same or not - depends on you or the selected topology, respectively (unity gain, gain-of-two, equal component design).
EDIT: Answer to your question regarding pole-Q:
The classical normalized denominator D(s) of a 2nd order lowpass transfer function is
D(s)=wp^2 + s*wp/Qp + s^2
with pole (angular) frequency wp=wc (cut-off) and pole-Q=Qp which gives you the amount of peaking of the transfer function at w=wp=wc.
This denominator form has to be compared with the actual denominator which is derived from the circuit. From this you can derive the formulas for the various componenets R and C. Note that these formulas, of course, can be found also in the variuous publications on Sallen-Key filters.