I tried to play games with a maxium of 48hs to respond, longer I get bored. Also while playing more than 5 games at a time I make too many stupid mistakes, and again it becomes boring.
3 games at a time is the best for me.
I 'd prefer to set a board for each game, and I can only do it when playing few games
'Quality over quantity' this is the key to getting the most out of Online Chess.