Third time is a charm. Thanks to a clever post by Donquixote I figured out where I went wrong with tutorial one.
What you need to do is:
In JRummy, home/data/data make a folder to store your user data for your Google accounts, for example I use the number 1 for folder name
Setup folders in there to store each individual account in. I prefer numbers since my emails are numbered. It's up to you.
Make sure you are signed into the Google play accounts you want to be able to switch to easy, doesn't work unless signed in.
Then when you are done with dungeon / boss exit mod
Go to JRummy (account folder) and copy user data for account you want to switch to
Go to com.igg.castle clash files and paste over
Then run mod and go into settings
Select Google account that you pasted
Reconnect and now you are on that account!
Rinse and repeat
If you need help switching accounts in order to save them please see my previous tutorial: