No, my straps never taper.
Toshi Straps are built using traditional techniques in the vintage “Pre-V” style, which means they are double layered, parallel width straps. This means that if you choose a 24mm wide strap it will be 24mm parallel and will therefore need a 24mm buckle fitted. Over the years this is the style of straps I’ve become associated with and it is the style of strap I wear myself.