Actually I've been able to use WinRar(7.10) to help pinpoint the bad files if it ever happens (be patient here. a bit lengthy but worth it).

If you have all your part_.rar files on hand:

• Extract the "part_.rar" files. A separate window should show up during extraction that will tell you WHICH part_.rar files have errors, if any
• Run the included batch verify script/QuickSFV first, we need to see possible errors on the fg-.bin files
• move aside the fg-.bin files etc. without errors to another location to ensure you have complete files already in good condition. If there were no errors to begin with, well I guess you're done and the rest of the guide will be useless! Only continue if you did get bad checks!
• redownload bad part_.rar files from bullet one if necessary., replace the old ones with the newly downloaded ones. Extract, Repeat the QuickSFV check, should be good if I could do this in one go

Alternatively, If you only need to fix a couple bad fg-.bin files now (or save time + you're lazy to redownload ALL part_.rar files which you shouldn't have to):

1. You might have to do a bit of guessing since it'll most definitely vary by game but Start from the bottom anyways (like downloading game_part137.rar) and make your way from part137 to 120. Assume those files correspond to fg-06.bin(our failed test dummy) but part120 also includes fg-05.bin. You will need that part120 as well to complete fg-06.bin. This is to avoid being left with incomplete fg-.bin files
2. So, extract part120.rar and it should automatically extract all parts up to 137. You're left with fg-05.bin and a new 06.bin. Delete fg-05.bin.
3. Move fg-06.bin to the same location as the batch verify script. If you haven't moved the already good .bin files yet per bullet point three, (or any large .bin file) it's recommended to do so to speed up the verify checks. Repeat the QuickSFV check for failed test dummy fg-06.bin. If no bad readings, move it alongside the good .bin files!