The problem with boot rack or Trunk carrier on a Miata or Mazda mx5

I took some pictures of a design that I came up with to over come the problem with the convertible Miata. That is to carry bikes or surf boards, kayaks etc. I think the car is great but have read so many people want to have more use out of their cars. Going to the beach or out on a trip. I thought of a rack design that will take any normal rack that fits onto 25mm tubing to carry either bike, canoe or any rack fitting from the manufacturers, Thule, Saris, Atera etc. This will enable any rack fitting to be fitted onto their Miata or Mazda. To carry a bike, canoe, surf board, kayak.

What do you think