Don't worry about the diatoms. They are standard in a new tank, and they will burn themselves out sooner than later. They feed of silicates, so as long as you are using RO
water, they will disappear fairly quickly.
If i were you, i would wait to put anything in the tank UNTIL you come back from FL. There's no need to buy a CUC just for the diatoms, since they will go away on their own. I know they are an ugly part of a new tank, but don't fret.
Also, CC will become a nitrate factory down the road since its rigid shapes and sizes allow for detritus to fall between the pieces. These are the areas were your clean up crew can't get to, and where it's hard to reach with a python hose(or any hose for that matter) to clean up. I would definitely recommend a sand substrate, but if your set on having CC.. just be sure to do regular maintenance on it. There is definitely nothing wrong with it as long as you keep up with the cleaning involved. Just need to dig a little deeper to get all the crud out.
Pictures would definitely be nice, but i'm sure we can wait until you get back from FL. No rush dude!