First, thank you for this, it looks wonderful!
Second, please forgive this ST newbie, but I’m trying to follow your directions but still learning the process.
a) I have the Universal Virtual Device Type Handler (thanks @Mike_Maxwell!) installed and published.
b) To create the Virtual Presence Sensor, you use +New Device on the IDE under My Devices? If so, I did that already.
c) I went to IFTTT and attempted to do your step #1, but it couldn’t find an ST switch to turn off.
I’m sure it’s something stupid I did (or didn’t do), so please forgive me. Hopefully, other newbies can learn from my mistake.
Michael
UPDATE: Ok, newbie found his own answer 
Make sure you update your Smartthings settings in IFTTT to allow access to your virtual switch(es).
Thank you again!