I made my own hook out of a piece of polyethylene. I bought some HDPE from ebay (search forHIGH QUALITY H D P E PLASTIC 3 MM SHEET GASKETS SEALS CHEMICALS CRAFT DURABLE). You could use an old plastic cutting board. It's easy to make and you just slide it onto a waist belt. It works fine. I used something like this as a model.

I also made a waist harness based on the Dakine Solo Wing harness. Fairly easy to build and also works well. I used scraps of bags and webbing and stuff I had in my junk box. It cost nothing but time. It's very comfortable.
I stopped using a harness. Yes it makes a big improvement in upwind angles and the amount of power you can hold. I was worried about bagging out my wing. It's alarming how much power is going into the wing when you're cranked over and doing a long upwind run. The apparent wind is huge. I didn't love having the harness lines hanging about either.
The one thing I really liked about the harness is I put a kite handlepass leash on the back. It was easy to quickly remove the leash at the end of a session for the carry up the beach. I don't do that anymore because I got a smaller board and mastered carrying the board and wing together.