I would apprecaite advice on the following questions on theBigBox Dual. Firstly what length of M4 screws are used to hold the Hybrid Titan Extruder to the Hybrid X-Carriage? Secondly the build manual calls for 2 x M3 20mm Screws to fit the IR Sensor to the Hybrid X-Carriage. I found that 20mm is far too long and 15 or 16mm was required. As there are no screws in the kit I had to cut my own. Is this a build error or am I missing something? Thanks, Neale.