Well, here it is: http://www.racedepartment.com/forum/threads/reduced-tyre-wear-100-race-length.75617/
Values should be 3 (Australia), 2 (Bahrain, Spain UK,), 1 (Malaysisa, China, Monaco, Canada, Germany, Hungary, Belgium, Italy, Singapore, Korea, Japan, India, Abu Dhabi, United States, Brazil).
By the way, I'm not sure if this had any effect, but, I just noticed the front/back_tyre_wear values were set to half, since I started modifying while I was using the 50% database here. I didn't change them, because I don't plan on testing yet again to see if there are any changes. Thought I'd let you know though.
Those values have an effect, so sadly your test results are incomplete.