I looked at those tannoy cabinets a few years ago. I had detailed plans and I would say you need a major woodworking shop and much better skill with precision cutting than I ever had. I made back loaded horns for a pair of Lowthers instead and while it was no picnic it was certainly easier to cut the more than twenty internal parts and have them fit than it would be to cut the thirty to forty inside the GRF cabs. The pieces are all at different angles and setting them up and aligning them would be a total pain in the ass. That said, I've heard a pair of the original tannoy GRF cabinets like this and they do sound impressive.