HA had a good tourney where you had a whole week to play the games, instead of specific time of the day. so, you could have a speed tourney that lasts the whole day or 2 and set up a minimum number of games to play. dunno how you wanna have the winner. it could be win percentage or an objective.
I hesitate to sign up for tourneys with specific time slot cause I'm on call and things unexpectedly come up (I prefer avoiding no shows). but, if there is a 24 or 48 hour window to play the games I'd be more interested and probably other players cause it wouldn't depend on time zones.