Looks good, but how much does it weigh ??
it's surprisingly lightwight, the tube is Anticorodal 6082 alluminum with 2.5mm wall (some bits, like the front cross beam that only needs to stabilize il thinner in section) , but can be done safely all in thinner tubes, my requirements were for heavy duty clamping for camera rigging. The payload of the original roof rack is crippled by design, the mounting points are ridiculously thin at the bolts while the profile of the frame is well designed and sturdy. With a little reinforcement on the inside of the body panel in the roof section there the orginal bolts screw into a thin pressed sheet of metal the payload can be significally incremented, while I do not advice to carry more then the raccomanded original load for omologation compliance you can feel much more at ease in case of sudden decellerations!
The large diameter of the tubes also comes from cinema standards but for general use a 35mm with 2mm section tube would be Ideal, more then adeguate to bear the usual loads and all the hardware is way cheeper and quite easier to bend to perfect shape unlike the 45 o 50 mm.
The frame shape, especially the double curvature of the bend gives very good strenght/weight ratio while being flexible enough to absorb critical load peaks while offroading, for light cargo the front supports are not mandatory but they help minimizing vibrations and flex. The tube fittings can be chosen from the kee-lite cataloge ( kee-klamp alluminum series ), more expensive but also much lighter and fancier, similar to the speed-rail american system.
The only really overkill components are the central supports which I intentionally designed and had manufactured oversized both in lengh, section and material ( heavy duty truck frame high tensile steel ) from which you can easily lift the hole car. I added a third heavy duty bolt in the rear of the support, coupled with a reinforcing shaped flange in the inside of the roof to acquire the perfect torsional rigidity, the load on the front supports is minimized, they act mainly as stabilizers, and the rear mounting points at the original roof rack attachments plates have been beefed up in size and rethreaded to accomodate a marine grade stainless M12 steel eyebolt. Not so much for load but rather for safety in case of accident and avoid stripping from the pulling from the camera gear rigged to the frame.
I raccomend going for a standard tube size from the light rigging world, this way you can use the super convenient quick couplers and clamps to attach all sorts of equipment from mud skids to accessories, tanks, showels, bike/canoe/ski/boards racks, storage and so on, it becomes like lego.