Diagonal works? what do I need next?

[ilikesound]

Hello. I posted a thread a while ago asking for help with acoustic treatment. Well i havent got around to it until now. Someone said there that i should try diagonal orientation aswell. I did and it measures very good. Should I leave it like that and treat from here or is it really better to have them set “normally” in front of the window?
room dimensions are 426x426x 250cm. Sorry for the mess ill take better pictures if needed.

Please, what kind of absorbtion do you think i need? (density,dimensions, location etc.) where should i put those two closets?

Thank you very very much.