The amount of generated players will vary proportionally to how many players from actual teams are up for sale. The noticable wave of them happens within the first couple hours after new day starts, but if there are many teams selling, there won't be many generated. So, try to find when people aren't selling on your server. Happy hunting, but don't forget, actual teams will sell off their players they bought that had been generated as well, and this can be easier to get, and if they are developed as you desire, can be a good value.