Howie I suspect you are fine the way you are. Depends little on how close you sit though.

I agree with Jerry not to raise the center speaker for the reason he described.

However, the Axis settings were NEVER designed to compensate for differences in individual speaker heights. It was designed to raise or lower the entire image.

You might give tilting 8K's heads down a tad though. It's a cheap easy test.

http://www.meridianunplugged.com/wiki/index.php?pagename=DSP6000%20Analog%20Axis%20Tilt

- Fiddler (IMHO)

If you think listening to music is fun, try learning an instrument.
HT: G61RSL, 4x5K, 5.5KHC, 2xSC6000, Transporter, HD621, Philips BDP7501 4K, Tivo, 65" LG OLED 4K C6
Computer: Foobar2000, 5K, Mojo, HiFiMan HE1000 V2