Hi Chris, thanks about trying to help with this one :)
So here's (hopefully) answers to everything you asked:
1) using the tint image from your tutorial here's the shot of the inspector of the texture: https://www.dropbox.com/s/4dl8qairfqypy8e/tint.…
Unfortunately that still doesn't work for me - as per my original screenshot the tint map shows like a white square in the scene editor and I can't overlay it correctly over the scene set :(