Oh, I lurk :-D Reef is drained. Kessils acquired. Just need to get a new sump setup (and purchased) and some ADA and hardscape stuff. I'm a bit slow to re-start :P I guess I also need to clear out some more old gear from the garage too.
Garlic, having planted many tanks, front to back depth relative to width is quite desired. 40g breeders has really good dimensions while 55g have (imo) terrible dimensions. CO2 is necessary for some plants and light levels. Decide what you want there and then decide how important CO2 is.
As for the sump, that is my plan too. Gets more equipment out of the tank. Of course, it requires an overflow of sorts (which I already have).