I've written a draft for this.
Please read the attached document, see if it has any value for you.
If you like I can expand this.
I've already opened isses for new version of loop-aes, util-linux, aespipe.
Steps to Reproduce:
Created attachment 61075 [details]
This is my draft README.
Created attachment 61076 [details]
So you get more complete view.
You can have a look at http://wiki.suspend2.net/EncryptedSwapAndRoot
Remind me if you want to do it.