I’ve put a tweaked version of my previous post (Moving a Linux installation to a new drive and encrypting it) up on Manjaro forums as a tutorial. You can check it out here.
I needed to change out the drive in my light laptop for a bigger one. Of course I didn’t want the hassle of OS reinstallation 1, so I decided to move my Manjaro installation from the drive to the other. My install was, regrettably, unencrypted 2 - I wanted to fix that during the move.