Agreed

Penknives have been shown in old catalogues with three blades (Sheffield) so it's a pretty 'open' term

As for size, I'd be more liberal, say 3 3/8" maybe? I have a CASE Redbone single-spring that's Stockman 47 size....and heard it called Large Penknife ...but that's a bit far maybe

I do like a blade each end single-spring knife in any size mind so I'm trying to tell myself that Charlie's latest and possibly greatest offering is not a City Stockman but a Stock Pen

Many thanks to
Old Hunter
and
waynorth
for their recent and wonderful additions to this thread

Bruce & Charlie I send you season's greetings, may your Christmas & New Year be peaceful and rewarding for you and those close to you.
Thanks, Will