Just registered to say a huge thank you to you all for this excellent guide and for writing this software.
I followed the guide in this thread and just wanted to add, that as a user of a recently patched paperwhite (5.12.3), I got to the end of the installation guide and KUAL was not visible.
But by following
the instructions from this thread and running a search on my kindle for ";mrpi" while having Update_KUALBooklet_v*_install.bin in my mrpackages folder things worked if anyone is having a similar problem!