mate that way overboard what you've done there ey, 200 x 100 (8 x 4)for top and bottom is silly same goes the 100 x 100 (4 x 4) for the legs 75 g is around 280 odd kilo's you could hold that just using 90 x 45 all round. fair enough you want to it be strong but that way too much. how are you gonna be able to lift it coz its gonna be pretty heavy. trust me mate im a carpenter and build houses for a living and know about how much timber can hold.