"Least Recently Created"

This doesn't work at the moment, as only 16 bits of the ctime are used. This is a bug in all 2.0 betas so far, but will hopefully be fixed before ship.

You only got a few files with ctimes, because only 2.0 betas (not 1.0) set ctime when a file is imported.

The n/n thing is unrelated; 2.0 betas just import the TRCK field of the ID3v2 tags as a string, and some taggers must these days be putting n/n in the string (as allowed by id3v2 2.3.0)

Peter