Meguiars NXT Generation Tech Wax 2.0 and some questions about it !?

Good evening Lackpflegefreunde ! Today it was time again. I drove the car through the washing system (exceptionally). After the car wash I found an unsightly light scratch, which pulls from the front fender to the rear, with the fingernail not noticeable, but visible, especially in the sunlight. I was almost shocked! Since the paint itself is still very unharmed, I could not leave it on me…! I still have a brand new one in the basement Meguiars NXT Tech Wax 2.0 found, which is about 3 years old. Optics/consistency and fragrance still very good, which is why I tried it according to the application instructions, in the hope to get the strap away with it. 80% I managed to do it then, and I am actually very satisfied about the result. The fingernail test… just brilliantly smooth ! Thus the whole car treated. Rucktzeck were 3 hours around Now I have of course still the one or other question about it u and hope to get help/tips from you: 1.) Would I have had to treat the varnish before growing? The varnish is visually very well maintained. 2.) Would I have got the scratch off with another Meguiars product 100%? Perhaps with which one to treat afterwards? 3.) I also used the wax on the disc, since on the instruction it is not said that it should avoid glass. The discs have become very clean and also sucked. So I have of course operated all the windows. 4.) How long does the Wax layer last when I wash the car by hand every 3 weeks? A few more infos about the car: Color: VW Silver Leaf Age: EZ 03/11 Condition of paint: maintained, until now a visible light scratch as described above. Thank you for the efforts you are making and your support! Nachti and LG, Maasta