There will be cave to corys, ill put 3 flat rock (with 3 enter space) then ill put pleco cube against them, so cubes will be cave to plecos and behind the flat rock will be cave to corydoras.

Look from front

Is that good idea? Pleco cubes and rocks are %100 natural. Tank is 100x40x50, this big cave probably will be 100x10x20h size.