Given the thermal mass of the board in and around the BGA the profile should match that of the replacement solder balls (if the device has been reballed and will be used a the replacement device) or match as closely as possible the profile of the device vendor’s data sheet of the solder paste printed.
There are several “rules of thumb” when zeroing in the process of reflow profile. It is good to learn about the thermal characteristics of the PCB when trying to dial in a reflow process profile. One of the best ways to “learn” about the thermal characteristics of the PCB when there is only one PCB and there is not a profiling board available, is to use what is learned during the removal process to help “dial in” a reflow process.