straighten UVs, increase padding to bigger number, enable antialiasing also if you're going to put the camera that close, you probably need more geometry
3.02 has a refraction shader that will enable you to do this. It's not out yet officially but there is a preview build posted in the FB group: https://www.facebook.com/groups/ToolbagUserGroup/
I've opened up the max file that comes with the tut. Is there a reason why the Gamma & LUT settings are enabled and set up to 2.2 instead of the default 1.0?
No! I would be thrilled for my work to inspire and enable others to do their own. Could there be a bigger compliment to your work than to continue it unpaid for you?
What you are looking for is the Shadow Catcher object. Scene -> Add Object -> Shadow Catcher. You just need to go to capture settings and enable Transparency.
I've seen this asked for before. There's no direct tool for this, but you could duplicate the mesh and use the tweak tool with background constraint enabled to get a similar result.