EventProcSleepTime changes the amount of time that the event_demon will sleep if it does not find a event in the database for it to process before waking up to check the database for events again. If it is not set, it defaults to 5 seconds. This value is set in seconds.
Adjusting EventProcSleepTime is not going to help in regards to limiting the scheduler to only the processing of SUCCESS events.
If you need the scheduler up to process incoming SUCCESS events but do not want it starting anything else then you would want to start the scheduler in global auto hold mode (GlobalAutoHold). That would allow the scheduler to still process the incoming SU event but for other events such as STARTJOBs, the scheduler would process the event but not run the job. It would place it on hold.
For more details see: