Diffusion - The scattering or random distribution of a sound wave after striking a surface.

In my opinion (i think most will agree) that after the original source (instrument, amp, etc..) the room that the instrument is being tracked in is the first stage of EQ.

Hello fellow Acousticians,
After finding an extra room that will for mixing/mastering, fallowed by then picking the right monitors for your room and ears, finding the best monitor placement and listening position within the room, next step is creating an RFZ, right?

Okay... so I've been researching poly-cylindrical diffusors...

Someone check me on this please:

What would be best to use to control the first reflections from my monitors if the ceiling is only 7ft 3in. I have some OC703 panels i'm putting above where the drum kit and percussion will be and i'm wondering if I should save some panels to control reflections above my mixing setup or if I should have some diffusion there.