I have the CAD design if you'd like to see the plan for it. I will say making it out of steel ended up a bit heavy and the roof box itself is a little big. I'll try get you a link to download the file.👍
Top tip would definitely be get proper Roof bars, a lot of the work I did was fairly stupid looking back on it. And if you dont have a welder or certain tools, it might actually be better buying a cheap pre made on, in my opinion.
