First of all, that is a good looking tank and a great start to an Amano style tank. However, I feel that the two rocks you have chosen, although differently shaped, are too similar in size. The largest rock, the
"oyaishi," should be about 50% larger than the second largest rock.
Also, I would avoid the even number two --aim for an odd number like 5 or 7. Try incorporating several smaller rocks to accent the two main rocks (which seems to be what you're aiming for).
Been wanting to say this, but never got the memory Instead of buying another rock, a good alternative is to further push down the one that you want to be the smaller rock. You said you have 3 total, right? And moderators were saying the 2nd rock should be 50% the size of the largest one, right? So why not see if you could push the 2nd one deeper into the substrate? That way, you don't have to risk messing up the your aquascape and also can save you some buck and time. If your substrate is deep enough then there shouldn't be any problem in doing this. I thought of this when I was doing my own maintenance and wanted to tell you ever since this past weekend but forgot. Hope it wasn't too late
Hey, I think I've seen this somewhere before.............hm..........interesting. Yeah, I think I really have!
No problems, man. I also did the same with my rocks. The 2nd one wasn't that much smaller than the largest one. So I suddenly thought why not just push it down to make it visually look smaller than the largest one! Hope yours will work out