I dont know about those drarfs, but a Volitan got one of our guys at the warehouse right in the back of the hand. Have you ever seen a 6'2" 210# fireman cry like a baby? How bout a hand easily mistaken for a red balloon? Those aren't nearly as funny as the look on the emergency room personels' faces when you ask for Lionfish antidote.
They do get weaker with age in captivity if they have no reason to have venom, (lack of threats, etc.) however, weaker is a relative term. It's basically like the difference between being stung by 500 wasps simultaneously, or 250.
IMHO, Since this is a deffensive device I would venture to guess that the young ones pack as good a wallop as the mature.