as asked via twitter, here is the *.stl of the holder.
The hole in the holder is following the curve and upwards. so please look it that!
Switch it to YOUR correct needs, RHCP / LHCP...
Middle Hole is 8mm
Print as many as you need.
use what you have PLA
DONT USE material that isn´t gigahertz usesable!
If you are not sure. Print something - cook it in your micro and if it heats up it is not useable!