cookingandpie the plastic gear has 40 teeth, the brass pinion gear on motor shaft is 11 teeth

cookingandpie great question. i'm quite sure i know the correct answer, as i ran into the same issue. if you get the version of this quad with ELRS built in to the flight controller, then it has firmware v2 of elrs installed - which will NOT bind with any elrs tx module running v1 firmware. however, if you get the version with no built in rx, then it has a full uart to solder in your own receiver to it - which can be any elrs receiver. and this RX can be running firmware v1 of ELRS and will then bind with any elrs tx module running v1 firmware

cookingandpie yes. it will take a 19mm camera - just like the Ratel 2 fpv camera

cookingandpie i weighed a few and the average weight of one battery is about 13.5g (btw my batteries are about 3 years old - if that makes a difference)

cookingandpie Obviously a pure coincidence. They share the same thickness of carbon too

cookingandpie yes - you will need to solder the wires of the xm RX to the flight controller. the qx7 will already connect to the drone, but the xm will give you better range

cookingandpie yes, i think so. you will need to solder the 4 wires of the cf receiver to the flight controller. check out the relevant happymodel frsky spi flight controller board to confirm and see where the wires need to be soldered. its a small board so wont be easy to do.

cookingandpie use should download the free software Betaflight and install it on your PC - and run it. then connect the quad to the PC with a USB cable. then you will see various options regarding setting up your quad the way you want it - including selecting which aux channels will be activated by which switch on your controller. usually channel 5 (or aux 1 is set aside for arming disarming your quad)