Hello Kevin,
tcode PFAL is only the way to go for the Initial data transfer. All updates should be done using Job RBDMIDOC which is creating IDocs based on change pointers. The processing in eRec should be asynchronous using report RBDAPP01. Make sure to define a variant for RBDAPP01 which sets the package size to 1 instead of the default of 5 as parallel processing resulted in the loss of relations between objects for other customers.
Kind regards
Roman