gearchange

Sometimes a custom component simplifies your hal file. Here is my solution for a similar problem where there are two belts each with 4 positions. But because it's not possible for both belts to use the same position, it comes down to the same problem you have. For the ratios, I just ran the spindle on each belt combination and read the actual rpm with a cheap laser tacho and did some maths. But I did not have levers, and made a panel for qtdragon which Chris "borrowed" for the qtdragon docs.

github.com/rodw-au/vmnmillqt/blob/main/scalebelts.comp

Rather than LUT5 look at using a match_8 for each gear.

Alternatively, a mux_generic with 6 bit inputs could provide the gear number, or a pair of them could provide the speed limits.
Your HAL file would only need to define inputs for the valid gear positions, not for all 64 possibilities.