I know this is a somewhat old thread. But I just purchased Kindlean and it works charms on my KT 5.1.2 - no issues at all. The diags > reboot > disable diags gymnastics may be a bit frustrating, but considering I always put lots of books at once is a no issue for me, as I do it less often that way.
BTW Thanks to all in this thread that helped me find the Kindlean to manage collections on my KT. Sad Calibre is of no use atm.