GreenTDI, I started a thread about Eco-driving the TDI diesel that you may find helpful.
https://ecomodder.com/forum/showthre...tml#post621801
FWIW I have not had good luck with smooth wheel covers on the Golf. I have tried them multiple times both A-B-A and over several full tank fills and they do not seem to increase my mpg. They may actually hurt my mpg. Heresy!!! Julian Edgar's book quotes several studies showing why my results may be correct, at least for my car. I need to start a thread if I can ever figure out how to add photos.
What transmission do you have in your car?