I made my 10 gallon sump myself too. Looking at your drawing, I can see you are making a really creative sump!
1. Well, first off, the first thing I noticed were bioballs. Bioballs are the source of ongoing controversy when it comes to phosphate/nitrate production. In my opinion,if you have live rock, get rid of the bioballs. You don't really need them and you seem to have plenty of filtration going on. Maybe replace the bioball area with a sump or just some fragments of live rock?
2. In the area next to your bioballs where the first baffle comes up before the overflow, I am not sure if it is a good idea to put holes in the baffles because it kinda defeats the purpose of the baffles. You might have decrease bubble removal from the water entering the holes.
3. On all of your dividers in the sump (baffles), make sure that they are not too close to the top of your tank like mine turned out. I didn't think about a power outage and how the return line siphons the water from your tank and overflows my sump. My baffles were put about an inch and a half from the top and when my return pump goes off, it would overflow. So, i drill a 1/8 inch hole in the return nossle in the tank that breaks siphon immediately after the pump shuts off. It still gets pretty close to the top but its okay. Oh and on the last divider, alot of people just put a piece of sponge.
4. Make sure your CPR skimmer will even fit in the 10 gallon sump. My skimmer didn't fit. I think the cpr has to have the pump at a certain depth in the water, but i think you said you will keep it in the tank.
5. You seem to have alot of stuff going on in your tank! You must love your fish as I do! But remember, your live rock should be your main
biological filter (according to the pros here). Also, you have a really awesome setup so far. CPR's are excellent skimmers, and the Emporer 330 is a really good filter! Are you sure you want to upgrade to the fluval? Whats good about the emporer is changing the filter bags is easy, and you can put the bags of carbon right behind the filters because there is a space made for them there. Since most reefers only use carbon maybe one week a month, it would be a hassle to keep cracking open that fluval to take the carbon in and out. Oh yeah and take those bio wheels out. Just use it for
mechanical filtration and let your rock be the bio. Emporers are also good because they create alot of surface movement (yeah, but they do hang off the back of the aquarium).
6. Research on the benifits of a refugium. I think that place where you would keep the bioballs would be an excellent place for a refugium! just put a little rock in there and some macro algae and it will help to stablize your nitrates and ph swings etc. overntight. you can also keep a naughty fish in there or grow some copepods.
7. If you don't have live rock and have a fish only tank, disreguard everything I just said and I am an idiot.
Hope that helps!