Wow, I just finished reading your thread and its amazing how we are designing our tanks so similar. I actually talked with Derek and was going to go with Miracles but glass scares me. And living in an apartment I couldn't take the chance. I got the 1" acrylic for the look but I could swing a bat at it and it wouldn't break (althought I would be pretty mad).
Actually, I think I was the first person Chris made an external overflow for. I told him I wanted the whole back to drain but he wanted to make sure the integrity of the tank wasn't comprimised. He made it just like you are having Miracles do.
Now that I have a good physical understanding of what happens in a tank, I'm doing the ssb thing now also. I've seen the bb and dsb people say ssb are bad, but the best looking tank I've seen in person, I mean no algae whatsoever and great corals, was a ssb tank with a big skimmer. Personally, I feel you get the look without the worry of it leaking nutrients.
I see your trying to decide what skimmer to buy and the best advice I can give is don't believe the hype. In fact, I wouldn't believe what most people say on RC to you in regards to this. Find some people who have the skimmers you want and go see them in person and better yet find someone who has several of the skimmers you want hooked up to the same system and visit. Also look a pictures of skimmate in good lighting. I was right where you were at a few months ago trying to decide between a deltec 702 and bk300 ext. You really should read this
thread on my local reef club; most of us know each other and its an honest discussion with some really experienced hobbyist.
I have a deltec ap600 and I've seen a few bk's. The bk's are awesome, they are silent, if you look at the bubble movement its not chaotic which I feel is important, and they look really nice. When I think about skimmers now I look at bombardment rate (how much air), contact time and bubble movement. Obviously recirculating needle wheel skimmers work, they increase contact time by recirculating the water (goes back thru the NW pump). You want the contact time to be longer so that the bubbles have time to draw the organics from the water thru attractive forces. But I don't know if going back thru the NW pump is best where the water and air after already being in contact, are exposed to some other serious forces and collisions.
That was the theory, but practically, I've seen a bk300ext get wrecked by a barr sk4220 and it wasn't even close. Then the guy added an ap701 to the system (600g heavily fed) and the sk4220 wrecked them both together. So that my my decision easier, but there is a serious wait time for a barr.