Stu has already pointed out that the 3 & 4's doing have rain gutters so that style of rack is N/A.
You are likely stuck with flat sides (or a rack with a flat portion designed for a RTT, which are out there for the platform).
I'd suggest diving through the depths of the inter web a bit and looking at the various iterations of this truck with RTT's on it to get a sense of what rack suits your needs best for a variety of reasons....
Meaning you can get it done with a Front Runner 3/4 rack and a standard (ARB) canvas RTT for sure...there are derivations of this for various racks (Baja and the like).
If you decide you want hard shell you can still pull that off with a flat rack, or even a prospeed (which is flat, but follows the truck's lines).
As I consider what I'm going to do I've got a nice sketch of the load area of my rack (a prospeed) and the footprint of a variety of hardshell tents (we considered, and then disregarded the soft style) that takes into account size, weight, cost, etc. The process of the research is going to give you a better sense for what works for you-if that's how you process info.
For a family of 5 I'd suggest a 3 person capable canvas tent, on a front runner rack, with an annex room that you can put up under it to facilitate spreading the family out. I don't believe I've ever seen a double RTT 3 or 4 ala what folks can do with the 110.
R-
Ray