CP was ex MIL and was never shy about demonstrating
then my previous comment clearly doesn't apply to you .. but your CP was a tad silly .. hard to explain at the enquiry if it turns to custard ...
I can remember Stuart's technique quite well .. and the brakes worked just fine as the aircraft crashed to a halt in next to very little ground run .. I can't recall actual distances now but, having read and analysed numerous cinetheodolite traces .. the bird did just fine in stopping ..
Point about STOL is that real STOL involves speeds somewhat less than the normal civil design standards require .. the problem occurs when something goes awry and the (modest) margin you have under civil rules is both not there and well and truly gone in the blink of an eye... usually with predictable consequences .. acceptable in an operational military environment but hardly justifiable for routine civil operations.
Can't speak to the Porter as I've no background with them at all .. other than watching an example on parachute ops ... does come down at an impressive rate ...