Just ordered some components from US suppliers, so they should get here fast:

10 x 3Pin 10cm Servo Extension Lead Wire for Futaba RC Connector Cable LB

10Pcs 2.54mm Pitch 0.1 1x15 15 Pin 15p Female Dupont Header Arduino Nano Headers

And then when those two arrive and everything is put together, then the spacers can be selected:

25/100pcs Black Plastic Nylon M2 M3 M4 Hex Column Standoff Spacer Phillips Screw