[baronep]

1) I dont think so. I believe on the toughbox, the drive axle is machined down to the correct diameter on the backside to accept the US digital encoder. I have no experience with your gearbox.

2)Correct

3)You will need to solder in some extra wire and then solder some female PWM connectors on the end to connect it to the DS. (White - signal; black - ground; red- v+)