I currently have in-ceiling speakers for rear surround duties and they are very close to 45 degrees angle from the LP. I had planned to 'upgrade' to an Atmos set up by installing another pair of in-ceiling speakers , and converting the existing ones into "Atmos rear heights". Although a few days ago when I did a quick measure up in the loft above I thought that I wouldn't be able to fit another set of in-ceiling speakers (having bought some already of course) at the same angle in front of the LP ("front Atmos heights"), in fact there is just enough room beyond the main perpendicular joist, (10cm to spare) under the piping which comes out of the tank in the centre of my loft, so I am hoping the speaker will be fine there (it will be 20cm away from the tank minimum). The other side is fine for installing the Atmos speaker. The front angle will be just over 45 degrees from LP. So now THX have suggested go for 7.1.2 in preference to 5.1.4 I am now wondering if I need to rethink my Atmos (future) plans. Should I continue to use the rear in-ceiling speakers as rear surrounds, and have one set of height speakers (at a different angle to the LP, i.e. more overhead), or will this configuration be too muddled, so I'm better off without rear surrounds. I cannot fit rear surrounds to the rear wall - window means too close to corners if I went with another pair of MA RXFX to match the surrounds, and, moreover, Mrs McSpongy said "NO MORE SPEAKERS ON THE WALLS!" Thanks for advice.