Aquascaping-change

[daddy01]

Hi,
I am new to reefing and am in process of changing from FOWL to nano.
I have added a Frogspawn and Ricordio (yuma) and Nephlea so far. My tank is a 30X12X21(17) with 4" sand/coral substrate=28Gal(?). I have a 130W Auqalight. I have frogspawn 7-8" from top and Ricordia same and the Nephlea 10" down in tank.
Now I am contemplating adding some Bubble coral, Red Goniopra, Green MoonStone hopefully.
My question is how much re-arranging can be done on aquascaping to accomodate these additions?
Jim