Hello there,
It's my first post here but I've been around for couple of weeks now just reading and gaining knowledge from this great forum as well as other places and books I found.
I'm planning to move my composers workshop to a dedicated room which is rectangular and very small (2,59mH x 2,1mW x 2,9mL = 8ft 6in H x 6ft 10ft W x 9ft 6in L). All plastered concrete.
I decided to do some reading and designing before I'd do anything but of course I am full of doubts and unknowns.
Main four corners would be superchunk triangle based basstraps 60x40 (2ft x 1ft 4in) made of european substitute for OC703 and same treatment on ceiling. Giving me 8 out of 12 corners covered.
On first reflections I plan to install panel absorbers OC703 4ft x 3ft 8in x 3in deep +1in airgap behind (frame). As you can see it's all absorption. But I read that in a tiny rooms like this it's all about basstraping.
I attached my design pictures exported from Sketchup. And I have couple of questions:

1. On the back wall from which I have 2,4m x 0,9m (8ft x 3ft) left - should I go with the Absosption or maybe Diffusion ? Or can I leave it reflective with some bookshelf, guitar hangs etc?

2. Do I need to install cloud on whats going to be left on ceilig 1,7m x 0,9m ( 5ft 8 in x 3ft)? And if so should it be BT or Difusers or maybe sth else like the mixture of two in example?

3. As room is tiny, in left bottom corner, behind basstrap I have air cavity and was planning to arrange some mic/cable storage there (basstrap would be on hinges with small wheels so it can act as door as well ), but maybe it would be better to fill it with rockwool?

4. Door and oposite wall - should I cover it with absorbers, difusors or leave untreated.

5. Do you think corner superchunks of that size are efficent enough or maybe I should go with let's say 5in panels with airgap. I decided to do super chunks as it wastes less space in my rathole and they are suposed to work better (wider q) .

6. I decided to wallmount my Event Opals as there's no room for them. They will be mounted on a face of superchunk (attached to concrete wall). They are big and i can't tatally soffit mount them because basstrap is to shallow. Is partly recessed mounting better than installin them on surface of basstrap?

The room will be used for composing/mixing, low SPLs and I want best freqency response/decay times I can make out of it, which is obvious. So if any of you guys have any advice for me I would be very greatfull.

Please forgive my English. And yes I need 4 monitor pairs cause I love em all.

Any help would be appreciated.

Jurgen