Remember that what's important is the overall leverage ratio of the system, and that there are enough variables that they're just targeting an approximate range based on how people typically use brakes and what feels comfortable. For example, where you apply pressure along the length of the lever affects the leverage as much as the pivot length that you're measuring. For cantilever brakes especially, the set up of the canti arms and yoke cable affect the ratio. And what feels really "grabby" (ie overleveraged) to some people feels normal to others. So there isn't a perfect pivot length for all short pull or for all long pull systems.

That said, it does seem that older short pull flat bar levers were pretty consistently around 21 mm, while newer long pull levers have a wider range. Most rim brake systems seem to target an overall system leverage of about 5-8 (ie the lever moves 5-8x as far as the brake pad), whereas disc brake systems are typically >10.

I've never used min-V's, so I'm curious to know what the leverage ratio of the brakes are. For reference, single-pivot caliper brakes are usually around 1, whereas full-length V-brakes are around 2 and center-pull cantilevers and dual-pivot calipers are both between 1 and 1.5. If the mini-V's are closer to 1.5, that would make it easier to set the up with long-pull levers without feeling underleveraged.