For basics of reversible circuits, you can see http://web.cs.dal.ca/~abrodsky/papers/rcc.pdf

Also, to simulate properly (low-power) reversible circuits your should use gmin=1e-15 or lower in spectra simulator settings.

I usually decided merit of reversible circuits by comparing charge flow to inputs to charge flow from outputs (using iinteg function on currents in waveform calculator)

Reversible logic has various parameters. Low Power, less garbage outputs, quantum cost; hardware complexity; less constant inputs; Finally it is optimisation or a compromise.