More than I prefer quite frankly. I had to fill the tank 8 times last month due to the amount of milage I'm racking up every week. Almost at 80k:-(
Post the pictures of your car and improvements over your method vs others and include points where others may have failed or could improve upon for education purposes..
I don't think you or any of us know if your body work/paint will hold up considering you haven't driven your Z to the lower limits yet... Speculation is Key.