This topic lists the steps necessary to determine a receiver threshold, based on how often you want to change journal receivers.
Do not make the journal receiver size too small, or the system will spend too much resource changing journal receivers or sending threshold messages. To avoid possible problems with a journal receiver exceeding the maximum size allowed on the system, specify a threshold for the receiver of no more than 900 000 000 KB if you specify a maximum receiver-size option for the associated journal. Otherwise, specify a threshold of no more than 1 441 000 KB.
Manual versus system journal-receiver management discusses options for managing your journal receivers.