I didn't have to modify my hook to open bottles, it works fine as is. It doesn't leverage the cap like a real bottle opener though, so I find I have to lift several flutes of the cap before it will pop off. It will definitely get the job done though!

I try and keep mine honed with an Oval Ceramic rod, the recurve edge makes it very difficult to sharpen on a flat stone. I think the easiest way would be a belt sander or the paper wheel trick, something with some give so that it follows the curve of the edge. The rod takes a lot of practice and patience, unfortunately. I find the yardhook requires my full attention too, so I can't sharpen it while watching TV. It's not an easy blade to maintain, but its cutting power is worth it.