It's a tricky one - that is pretty much more than anyone would regularly want to unpack- set up, launch - a heck of a faff and effort even for two people. Hence most go air floor if packing away each time (check the 'Which SIB' topic to save repeating all the same stuff) and something around 3.5m.
Bigger and especially with a heavy old 20 you will want a trailer for sure as Fen says but that of course takes away much of the SIB attraction.
It's all a huge compromise.
Not familiar with Boatlife (trade show?) but what looks simple and neat on a show stand is a different matter in real life on a muddy launch site, rocky coast or gusty wind over tide launch over a steep beach etc.
