Lots of the usual mythology and diverse personal beliefs/opinions as per usual when questions of this ilk get posted here.
This is nothing to jump into w/o doing a little research and reading.
Suggest that the OP just go and visit some layouts in his area, talk those people and get a more 1st hand direct input / response to his questions. Maybe back-track that layout that he saw at the show and talk directly with those folks since he saw there what he liked.
Space requirements are totally dependent upon what the desired objective of the layout might be for the individual. There are additional variables in play there as well.
