I love me some Zaino. It is one of two LSP choices (the other is Klasse SG) that I use for the winter protection as durability is great. You will get several comments/replies on the "look", but I firmly believe that "beauty in the eye of the beholder" and I really like the overall appearance of Zaino. For silver cars, it is one of the first products I reach for.
With regards to process, I don't have or use ZFX as I still have the old school Z1. I add a layer on a weekly basis after a wash so I don't have a particular need/use for ZFX...of course, your circumstances may differ and you may want to have ZFX for multiple layers in the same day. Something to consider is purchasing ZAIO as it will clean/prep the paint surface and you will not need to worry about any polishing oils that may interfere with Zaino...it effectively supersedes Z1.
Note: Added the below comments after my initial post...
As Dan mentioned, I also get about 3 mid-size cars (including wheels and windows) per Zaino ounce. I recommend using an MF application pad via hand so that you can keep product usage low...machine application is ok but the foam pads themselves will absorb (ultimately, waste) more than an ounce of product.
Unfortunately, the most frequently used Zaino products (QD and car wash) are not available in gallon capacities. In an effort to save money, I have explored alternatives. Z6 is a good QD to use...However, an alternative product that I have used without any compatibility issues is Meguiar's #34 Final Inspection. In addition, #34 is much cheaper especially since it is available in gallon form. Zaino car wash is a very good (albeit fairly strong) carwash, but I have used Duragloss 901/902 without any issues.
Zaino Z8 is one item that you should get along with Z2 or Z5 - In my opinion, it is in the top tier of comparable products.