What attracted me to The Smart Set specifically was it's self-proclaimed wit, the cover always subheadlined with "A Magazine of Cleverness" This kind of self-aware almost-pretentiousness, I think, is an interesting tone that most might consider to be more representative of contemporary writing. I wanted to see what kind of snobbish, high-culture wit was like back in the early 1900's.
The specific issue I picked was the 4th issue of the 50th volume, dated December of 1916. I picked this one because I wanted to get a feel for the magazine later in it's run, assumably when it's readership and subsequently the writers who submitted material would have developed a pretty consistent idea of what the journal was like stylistically.