1, About 1.5" with the ADM mount I had made.
2, USB only, there is no removable battery.
3, objective sizing on a thermal only deals with detection range, the luchs 2 is still at full price of 5kish, and the 35mm is perfect already, i wouldnt spend the extra as a novice.
4, there is an intuitive menu with different color settings and such, it does remember its last setting.
The buttonolgy on the luchs is one of my favorite setups in the industry, the closest thing to a luchs is a RH25, and you need a degree in IT to get that thing started and ready to kill. the luchs is a simple on and off button.