I just repacked my rudder stuffing box and found that the same piece of PVC pipe that I use to seat the C-Drive seals works well to help seat the packing material in the stuffing box. I also used a 1/4" (6mm) piece of hardwood to seat the packing.
In the USA a piece of nominal 2" Schedule 40 PVC pipe about 10 inches (~250mm)long works well. The dimensions of 2" Schedule 40 PVC are as follows:
OD: 2.375 inch/60.3mm
ID: 2.047 inch/52mm
Wall Thickness: 0.154 inch/3.9mm
Length: 10 inch/250mm--
SM #440 Cara
Deale, MD USA