sorry, couldn't find the other link, it looks like the company went out of business. i know there are other vendors, just this one made it into my favorites for lowest price. i will try to find the product again.
there are a few IBC tote projects to refer to. I think you may need to add more grow beds for that many fish!!
The standard rule is 1:1, but 3:1 grow bed:tank volume is possible. this rule of thumb is kind of like the WPG or inch per gallon rules we hear about. not exact and pretty general/only applicable to older technologies. the higher the ratio of surface area:Water volume the easier it is to get to that 3:1 "Max", but obviously your fish choice means you need to have it a given depth or greater.
for the 41gal system you could easily do a 48"x24"x8" deep tray. if you got the skills, DIY it and line it with a pond liner. my hydro trays are 8". i tried using a 6" and it was just too hard to tune the siphon.
there are a lot of successful projects out there for gutter pipe/ drilled fence post/sanitary tee etc, but you will find most of them run a countinous stream type of system for the reasons mentioned above. i did one with 2 liter bottles with the bottom cut off. a little work on the cap/screw on top and it will fit snuggly in a 1" T, so you can rig it up however you want. i had mine on a frankenstien vertivcal set up, and used the dripper splitters mentioned previously. it worked, leak free, but i have moved more towards whole beds filled with media rather than net cups. something about it seems better once you watch it in operation. it is sort of hard to explain. sort of like how you can "know" something is going on with your tank before the test kit tells you anything of value. I feel the excess media does a couple of things: increase surface area for micro organisms and root support, and reduced water volume needs to fully ebb and flow. if you do the reading, you will find that aquaponics systems are running at temperatures that would lead to disaster in traditional hydro (also know this from frustrating personal experience, good luck keeping your res under 80 in so cal with a 400W light and flood pump near by), and the supposed reasoning is that the increased bacterial population makes the whole system more robust.
i hope to start a journal on my current project soon, and encourage you to do the same, who knows maybe we can get a low traffic sub forum like the pond guys!!!
only problem for me is that i may have to move my system to the other side of the apartment so i can fit my table in the dining room (didn't think about that before