Charging resistance- help !!

[dhindley]

Does anyone know what resistance value (Ohms) the half charging resistor, shown fitted at the side of the light switch on the wiring diagram, is for a 1935 single with magdyno.
This model does not have a regulator.
Have searched the web but can't find the answer.
I have access to power resistors and will fix one in an alternative unobtrusive place, once I know what value to use.
Just completing final build of LH 250, only wiring to sort out.
Hope I can thank someone in advance.
Dave Hindley