O.C.D. Speaker placement

Mismatched differences between your ears/speakers by an inch or less should make no significent difference. If it does your should pick it up in hearing a slight shift in the stereo imaging towards the speaker furthest way. But that is only with your head in a vise. Moving your head about, or shifting in your chair, will cause a greater shift than that.

Rather than concern yourself with such minor differences in distances, you might re-direct your energies in perfecting not only the direct sound, but the sound reflecting off the walls, ceiling, and floors. And fine tuning your toe in. Doing so will improve your sound much more and will certainly challenge your OCD problems. This can keep you busy fussing around for years.

FWIW, IMHO, Exact measurements in speaker/listening position set up can be useful in initial set up IF you just happen to know what measurements should be, but can also be detrimental. Exact measurements can cause a reinforcement of nulls and nodes which are potentially problematic.

Get OCD about your sound, not exact/balanced physical measurements.

After some reflection I would suggest that you avoid something that, while it might help in initial speaker set up, would really activate your OCD to new levels.

Don't buy a sound meter and test disc and try to obain flat frequency response (at your listening position) as well as maximizing your systems potential to produce high quality sound, especially its ability to do 3 dimensional soundstaging. The odds are highly against success, so if you try don't say you weren't warned! :-)

Rok2id, I'll take credit for that bit of toe-in. I recommend it all the time, but for some reason I get little feed back - I think many folks here really are not into soundstage specificity as we anal folks are. FWIW, its biggest influence is the obvious, it reduces side wall reflections thusly making the on axis response much cleaner. A side benefit is that it will also change the reflection patterns off the ceiling, as well as all of the 2d reflection points. I think this works best in medium sized rooms where these issues predominate. Also, it can allow closer to side wall placement to widen the sound stage without lessening the center image's specificity. Lots ot trial and error though to get it right.

Mt10425, That's a benefit I forgot to mention. It has to do with the fact that the length of the on-axis signal from both speakers is obviously unequal to the off center listener (your wife), but this inequality is balanced by the fact that she will get a more on axis signal from the furthest speaker whereas the closer speaker will be heard more off axis. That signal is usually more rolled off in the highs (usually but not always - depending on speaker design). These different signals blend and give a decent sense of soundstage. You lose only a little bit of specificity. It ain't perfect but it can be quite nice, just don't tell her it ain't perfect or she'll grab your chair! :-)