finding good encoding parameters

[martinfrombern]

I've done plenty of encodes in x264 but one thing always interested me. Just to say at the beginning I can also draw some conclusions based on my own experience, so I'm looking for an answer from a theoretical point of view. When trying to find good aq, psy-rdo, psy-trellis parameters, is it good approach to fix psy-rdo and psy-trellis to, for example, default 1.0:0.0 and find the good value of aq ("good" from visual point of view, not ssim or psnr) with those fixed rdo and trellis values, and after that start tweaking psy-rdo and psy-trellis values with this "good aq parameter" already found.
Can this procedure even be extended for psy-rdo and psy-trellis (fixing psy-trellis and finding best psy-rdo)?