PI to PI Interface - History Recovery

How far back can you go on history recovery at startup?  Is there a limit?  Thinking about using this as a way to merge two PI Systems- one smaller on into a larger one and wanted to understand the limitations. KB00744 mentions this at the bottom as a possible way to do it (see below):

"Another way to accomplish this (if you have access to PItoPI Interface) is to perform history recovery with PItoPI for the points on the target PI Server and then change the point configurations so that the correct interface (OPC, RDBMS, etc.) loads the points for snapshot data collection."


The systems we are merging contain no batch data, so I am wondering if there would be any advantages to merging archives of the two systems versus doing it via PI to PI?

Thanks,

Scott