I did read up on those FAQ's already. I had gotten the magic number error on occasion with fsck, and the filesystem physical size mismatch error with fsck.ext2

These are the following values that I've tried for the superblock:

24576
24577
32769
98304
98305
163841
229377
294913

None of these produce a different result.
I used the big disk builder v6 when creating this drive.