Fresco I as side and rear surrounds -vertically or horizontally on-wall mounted?

[ML&Denon]

Hello all, I'm a ML "newbie" here. I recently purchased all MLs for a 9.2 set-up and am preparing for installation shortly. I have a Cinema I as a center, Clarity as Front L and R, and 6 Fresco Is for surrounds and rear speakers (2 surround speakers on the left, 2 rear surround speakers and 2 surround speakers on the right). I am planning on purchasing 2 Abyss subwoofers in the next 2 weeks.

Here's my goal for the Fresco Is: 1) achieve the best sound dispersion; and 2) that all are sonically matched. My question is:

1) if Fresco Is are used as surrounds, are they wall-mounted vertically or horizontally?;
2) if Fresco Is are used as rear speakers, are they best sounding vertical or horizontal position?; or
3) should they all be vertical or all horizontal? ...or even mix and match?

Things I know to consider:
1) The room is rectangular and already pre-wired where the top, long-side of the rectangle is the front;
2) the two left surrounds are on the left, short-side of the rectangle;
3) the two rear surrounds are on the bottom, long-side of the rectangle;
4) the two right surrounds are on the right, short-side of the rectangle;
5) the seating should allow for 15 people in the center;
6) there is already wall-to-wall carpeting;
7) nothing is mounted on any of the walls;
8) all the A/V equipment is in another room controlled via remote and IR repeaters;
9) 2 French doors on the bottom of the rectangle;
10) 9’ ceilings and 7 recessed lights.

Whew. Thanks in advance for your time for reviewing this thread. I’m hoping to read a response soon so I can get my theater up and running.