Why not put the put the driftwood that looks like a stick in between some rocks, pointed upward - and then tie some plants onto it? That way, it kinda occupies some space toward the top, and you'll have some green up there too
Great tank, btw!!! I'm going out to the field tomorrow, so I hope to be lucky enough to find some nice rocks to put in my future 29 gallon. lol, it'd be pretty bad if a geologist (well geology student) bought rocks for his aquarium, when he could very well be collecting them, without looking weird(er) than usual.
I may do the "fallen rocks" on one side, with the other side grassy, and full of plants. Sooo many ideas in my head... I need my stimulus check and birthday money already!!