So yeah, trying to interleave FMA & FMA:B was not a good call. With the possible exception of FMA 9 (still coming on my schedule), just skipping the first episode of FMA:B would have done fine.
Spoilers for all versions of Fullmetal Alchemist.
( FMA 3, 'Mother' )
( FMA:B 2, 'The First Day' )
( FMA 5, 'The Man with the Mechanical Arm' )
( FMA 6, 'The Alchemy Exam' )
( FMA 7, 'Night of the Chimera's Cry' )
( FMA:B 4, 'An Alchemist's Anguish' )
Spoilers for all versions of Fullmetal Alchemist.
( FMA 3, 'Mother' )
( FMA:B 2, 'The First Day' )
( FMA 5, 'The Man with the Mechanical Arm' )
( FMA 6, 'The Alchemy Exam' )
( FMA 7, 'Night of the Chimera's Cry' )
( FMA:B 4, 'An Alchemist's Anguish' )