Luke, I honestly wouldn’t worry about it. It doesn’t affect movies because you have the centre speaker physically locking the sound to the centre and if changing the distances by that small an amount gives you the result you are seeking, then go for it. IMO you will not be adversely affecting anything of significance. It's when people want to make big adjustments, say more than 1 ft, that the real problems arise. Chances arem if you ran Audyssey again you might get slightly different results yet again.
On a slightly different note, I once spent some considerable time trying to help a friend get a precise central image from his stereo speakers. We went through a lot of troubleshooting procedures and personally I just couldn't hear the off-centred vocal he was hearing, but we persevered and tried everything we could including moving the speakers, measuring the output voltages, rearranging some furniture and so on and on. All to no avail. After many hours of this my friend suddenly said "You don't think it has anything to do with my being partially deaf in my left ear do you?". My reply is not publishable on a forum
LMAO.....he was deaf in one ear? He should start with that next time. I agree trying to get a good stereo image is time consuming...but it's worth it when you get it to your liking. I was able to do some more careful listening lastnight and I believe I'm happy and will stay with the adjustments I made. Thanks for all the info. Luke