[Fishobob]

Gday Fellas,
Well let me start off by saying that I'm from Australia and over here we dont have anything like the range of products or the cheap prices that you guys in America seem to have. For instance over here in Australia a Turbofloater 1000 skimmer with a rio pump is $700! Also I'm a university student( marine biology at melbourne uni) so i dont have cash overflowing out of my wallet. So I'm looking to spend about $2000 setting up my tank.
Anyway, I am planning on having a 48x24x24 tank, 120 gallons US I think or 450 litres in Australian terms. I want to have two corner overflows with 1.5inch bulkheads. Firstly do you think these will be big enough enough? I want to run with a sump and a refrigerum. I'm not sure about running with a refrigerum in sump type setup because I think that there will be too much flow through the refrigerum. Though if any of you guys run with one of these setups could you please tell me how you have it setup and whether or not you prefer this to seperate sump and refrigerum.
So I was thinking about having one overflow flow into roughly a 20 gallon sump with baffles then a chamber for skimmer, heater, etc, then maybe a small section for a 5 inch deepsand bed then more baffles to the pump and the outflow. What do you think? Then I was going to have the other overflow flow into my roughly 20 gallon refrigerum with 5inch dsb, LR, and lots of macroalgae. I would then have this overflow back into the sump section after the skimmer part. I wanted to know is it wise to have this water bypassing the skimmer and going back into the tank? Also would the waterflow through the refrigerum at the same rate as the sump or would it be slower because its a different overflow and the water is then overflowing into the sump? I think it will probably be the same rate actually which is not what i want, i want the water to flow through the refrig at a slower rate
So should I just go a bigger tank underneath and just setup a refrig in one? What do you think??? I'm really not sure what to do and I'm planning on starting everything when I finish exams which is in three weeks
Also I would like some advice on where to have the returns. My lfs guy says dont have drilled returns, just have flexible tubing going in over the top. I dont like this idead. So I want to know is what depth and where in my tank should I have my return. I was thinking about having two returns at opposite ends of the tank up near the top of the water surface so just in case I do have a leak I only lose a few cms of water depth Is this a good idea?
Sorry about all the questions but if you could give me some advice and feedback on my plans, also the details of your sumps and refrigerums I would really aprreciate it.

Cheers! Fishobob