I'm not entirely convinced heavyweight spokes are necessary for a cargo bike
I think you’re almost certainly right, when the Urban Arrow XLs (cargo bike Ian is using) come with Rohloff hubs, they use 14/15 spokes with no issues. If anything I think the butted spokes are better and last longer than the 13g plain gauge spokes the Nuvinci are built with (as well as being easier to build and bring up to / maintain a decent tension)
@MCamb
I think you’re almost certainly right, when the Urban Arrow XLs (cargo bike Ian is using) come with Rohloff hubs, they use 14/15 spokes with no issues. If anything I think the butted spokes are better and last longer than the 13g plain gauge spokes the Nuvinci are built with (as well as being easier to build and bring up to / maintain a decent tension)