"A couple of folks that I respect greatly have advised me not to use a BCR with a PS2 5 volt board. (Regardless, BCRs are fine with the 3 volt PS2 boards.)"
I have quite a few locos with PS2 5 volt boards and have been using BCRs in several of them and haven't had an issue. Can you tell me why the folks that you respect greatly advised you not to use a BCR with the 5 volt board?
Thanks, Tom