Any ideas about where to start simulating such a circuit? Should the W/L 's vary from switch to switch? Clock frequency needs to be set to 50MHz with a rise and fall time of 0.5ns. I am allowed to use two ideal non overlapping clocks that can run from rail to rail (Vdd to ground).

 

Where to start?
At first you have to decide what you want to see as a simulaton result.
That means: Simulation in the time domain or in the frequency domain?