Car looks really nice and Zaino did do it justice. I agree with you Dust a little goes a long way and I too have had ZFX'd Z5 or Z2 that I had to throw away after mixing up 1 oz. I was able to do 2 coats on the car and a coat on the wheels and still threw away quite a bit. The last time I used it I used less product and of course had less to throw away.
Just for kicks I went just then and measured out 2 oz of water in a measuring cup and poured it in the Zaino prep bottle for ZFX'd product. The bottle is not 2 oz it is about 2.5 or 2.75 oz. So to get 1 oz to prep don't fill it half way more like 3/8 and that would be more representative of 1 oz. I'll start doing this and I would venture to think I wouldn't have much left over.
As another side note I have a bottle of DG 105 that I bought locally and it is the EXACT same color, consistency, and smell of the Z5 Pro that I recently ordered. Now I just ordered another gallon of DG105 directly from Duragloss and it is a yellow creamy color. Completely different from the DG 105 that I bought locally.