I favour my left sit bone, quite much actually. I know it's because my legs are different length, but there is really no problem and as long as I don't try forcing myself to sit dead center on the saddle, there is no issue. My body has ofcourse grown accustomed to this over the past 12+ years of riding and there is no point in trying to change this.
Even so, I did actually get some knee problems a while back after switching to a narrower Q-factor, and moving even further to the right of the saddle did seem to help, so to get me back closer to the center of the saddle, I offset the cleats (right shoe all the way out, left shoe all the way in) and added a spacer between left pedal and crankarm.
Perhaps a bit of a hack job, but it got the job done and relieved my pains. I still favour my left sit bone, so that was just to compensate for the slightly too narrow Q-factor really. I now sit as I did with the old wider Q-factor.
I did read somewhere a long time a go, that anyone thinking their legs are perfectly symmetrical in length, is 99,9% sure to be wrong. The body is very much asymmetrical left to right, we just don't notice it as we unconsciously make our own small corrections for it...
It seems that we have fairly similar body imbalances from readying this. I had a shorter right leg and as a result my left site bone/saddle area tends to get more sore/irritated/painful. The right side seems to always feel like it's falling off the side or not really up on the saddle. Anyhow, in the last week or so I have started sitting somewhat asymmetrically on the saddle, basically sitting with the saddle further to the left inner thigh than the right. This has improved saddle comfort noticeable so far so I'm interested to see how this progresses.
I know the situation isn't ideal however, it seems to be an improvement comfort wise vs. trying to making myself sit evenly or centered when my body really can't...