here is a link with diagrams that might be useful to you.
A raft bed will do best if you provide plenty of aeration to the raft bed and if you send filtered water to the raft bed.
If you only have a limited amount of grow bed, you can still get by as long as you only have as many fish as your grow bed can support. So for this first season I would only recommend about 1 fish per cubic foot (or 7.5 gallons) of grow bed. Well that would be for fish that can get to plate size, if you are only doing small goldfish, well then you might get away with a few more fish.
Hum I guess the link didn't work
here it is