I would mix in some D.Diandra at the back of the Pogo to add some contrast, the tops go a nice red under moderate lighting, stems are same green colour as the Pogo so it will blend in, nice tall fronds if left to grow, your lighting is strong enough for a decent HC carpet so the DD should redden up nicely. I would also plant some small crypts like Parva or Willisi around the rocks orientated to point away from the rock, just a few not too many, just enough to delineate between the Stauro and the rocks.
Edit- Should have said I agree with Paulo it needs a little red, but AR Mini would be a little too much despite me thinking this immediately upon reading your post and not seeing Paulos suggestion, on thinking about it you have two levels, broad leaf and pencil leaf, adding a broad leaf amongst the pencils might break up the symmetry you have going, the D.D is a bit of a half way house in this respect, stays narrow and tall and only turns red at the tips, this way it can blend in and add contrast.