I asked basically the same thing a while ago...well i just asked if a 10 would be ok for one actually...but the response i got made me decide to wait on a bigger sump...heres what everyone said...
1st, you have to have room for a bit of overflow if the pumps or whatever go out, so therefore you dont fill the whole ten gallons up. It'd be more like 6 or somehting and thats not really any added bonus.
2nd, If you were to divide the 10 into a sump/fuge/return area, there would be basically no sump volume again...maybe a couple gallons i would think.
They said some other stuff too, but i forgot...
also, you asked if you should have the fuge first, sump, and then return...i would thin that the fuge would have to be second, because in the sump, the skimmer would take out all the pods
growing in the fuge (if the fuge was first) therefore making your fuge useless...well maybe not useless but you get the idea.
I've got the same size tank too...srry i forgot to add that.
I'd try to set up like a 20 gallon or something...at least. but try bigger if you can..used ones are cheap.