1. There are two pins that comes with the tray. If you use a smaller one (most people do), it will perfectly fit into the storage compartment when assembled - no need to disassemble it every time.
2. Regarding the instructions - it has been noted before, and with all new shipments the factory includes instructions how to put the backs on, although it should be quite straight forward
3. The hydraulic arm can be adjusted (where it is attached to the storage...