My 3-person RayWay tarp is a scaled up version of the 2-person tarp, but with extra length since the peak will be higher relative to a 2-person tarp and so it needs to be longer to keep out the rain.
The material is Silicon coated 1.1 oz nylon, maybe 1.3 or 1.4 oz. per square yard. The tarp weight is mostly the silnylon, with an ounce or two for the extra-long ridge and side tie-outs. The two main panels are each 120 inches by 70 inches. I forget the beak dimensions. Thus the coverage is about 12 feet long by 10 feet wide. It weighs 1 lb 7.8 ounces, not including stakes.
I made a net tent, suitably scaled up, as well. It weighs 1 lb 4.7 oz, and it consists of a silnylon floor plus a whole lot of netting.
Two of us took the tarp and net-tent kayak camping recently and it was like the Taj Mahal, lots of space, very comfortable. For three the net-tent is a bit tight.