Could you provide a link to the tank your actually looking at so I can get a better visual than the discription alone leaves? I could probably help you out with considerably becuase I have 8 tanks that are 40-300 gallons that are from 1-3 years old.
I also work a LFS(newly established store front) that caters to saltwater only and provides tank set up and maintence services. I set up thier SPS/Clam system for them and pretty much call the shots on anything having to do with this sytem from maintence to ordering of live stock. I am also the one that gets to deal with the fish that are the picky eaters and problem corals, often taking many home to salvage them before returning them to the store again for resale, just to give you some background on where I am comming from on this post. Also serve as a staff member on another forum for saltwater fish/coral. Not claiming to be all and knowing but I do got a few laps around the block.
Your choice of lighting doesnt sound like a bad one. I personally would prefer to go 10K bulb though myself and just back it up with some actinic. I just find that the 10K's are a good balance between coral grwoth and color when a little actinic is added. It will also allow you to have the dusk and dawn effect in the tank as well if thats a mitigating factor for you. I have used several halide set ups and the one that I am currently favoring the most is ARO electronic ballast and 10K XM bulb set up from
www.hellolights.com. This combo has worked very well with some actinic over my displays and my frag tanks for SPS and Clams
I have had the misfortune of owning a couple of Red Sea Berlins when starting out and didnt care for them, in fact I woukld rather have a SeaClone instead! If money is an issue the Jebo for 35.00 is actually a lot of skimmer for the money!!! (Yeah I couldnt beieve it either but I had to try one of the Jebo Skimmers out just to see if they were all of that and a bag of chips-not the best of course but for the money, they work suprisingly well!!!) Euro-Reef skimmers coast very little more and are much better as are ASM (I believe thats the brand name?) which is supose to be a cheaper knock off of the Eruo-Reef. Thats my skimmer of choice!!!
A refugium of any size in my opinion is better than no refugium, but in your case with the tank size you mentioned I would prefer a bit bigger refugium. Not knowing the exact model of tank your looking at its hard to suggest something specific at this point but I will tell you bigger is much better when it comes to refigiums. The over the tank Gravity feed refugiums are the best in my opinion but often its not possible to install one due to visuals or space constraints. I have both above the tank refugiums, and below the tank refugiums and all have been a huge asset to the health and well being of all my tanks!
I would most seriously suggest some form of mechanical filtration to remove dertious and particulate matter from the tank. To not do so will involve lots of tank maintenance on your part with graval cleaning and running a diatom filter after blowing the tank down with a power head. Running a skimmer and refugium alone I feel wont be suffcient enough to provide proper filtration
These are strictly my personal opinions and experiences that I thought I would share. Your "milage" of course my vary....as each tank is a bit different and there are lots of ways to have a great tank and few sure ways to a bad one. HTH's....