Wow you gave me a headache with all that figuring ha ha. Some years ago I had a half step setup. Sometimes I think i actually had the hang of it. It was and still now about having enough range to get their. I purchased a Co-Motion Pangea Rohloff near 10 years ago. I prefer it over the half step with a triple crank. You probably could find the components to setup a half step. You would have more shifts. The shifts although challenging at first would give more useful gears. If you want monotonic gears you could setup one gear on a Schlumpf Mountain drive and seven or eight speed cassette on the back.