Specifications of the rear hub: 
Brand: BQ
Model: BQ-RH30021
Color: Black
Number of spoke holes: 36GTS
Type of brake: Disc (Centerlock)
Number of gears: Micro Spline
Freewheel system:    Pawls (6)
Points of engagement:    60
Type of axle: Thru axle Ø 12 MM
Axle included: No
Type of bearings: Sealed bearings
Average weight (GR): 301
Intended use: Tour
 
Data for spoke length calculations using the Sapim spoke size calculator: 
Total length of the hub (MM): 142
Non-gear side (MM): 36
Gear side (MM): 49
Hub diameter non-gear side (MM): 59
Hub diameter gear side (MM): 59
 
Link to spoke calculator: www.sapim.be/spoke-calculator