Why not some where in Mid town?
Why Flushing/China town or LES?
Reason why I asked 2nd Question: See I'm at Sunnyside..for me it takes 45 mins to get to Flushing in #7 train, to LES/china town 1 hour 15-20 minutes...changing 2 train...either from Queensboro plaza or Grand central. Now Do I want to waste 1+ hour just in transit to meet fellow hobbyist?? To Swap some Weeds, shrimps etc.
Say some 1 is coming from the Bronx, Brooklyn, SI...he has to take a(x)train to Manhattan then transfer to another(Y) train for either location mentioned. Now from Brooklyn to Manhattan say 45 mintues in a(X) train then another 1 hour in (Y) train to get to Flushing or other location or VV minute wise...So why not some where in the middle? It will be fair for all...Say somewhere in Bryant park(Time Square) area. This way all will rid only 1 train...#7 from sunnyside to Grand central...or #6 from Harlem to Grand central etc...If not all most train stops at Times Square or nearby station.
I may come I might not...this is only my opinion...One of the local member here long time back wanted to do same thing what you are planning to do but didn't worked out...
My parents live in Sunnyside and I work in LIC, it does not take 45 minutes to get to Flushing and 1 hour 15-20 minutes to get to Chinatown.
It take 35 minutes from LIC (Hunters Point stop) to get to Flushing, and only about 40 minutes to get to Chinatown...via the 7 to Grand Central and then the 6.
Anyway, Times Square/Bryant Park would be convenient to get to for everyone, but what's the point in that? There's nothing there and after meeting up, everyone would still have to travel to Flushing or Chinatown for the shops.