How to read a greneng

[Bjorn]

Alan, when you refer to the other elements in the greneng, apart from the ron dha, do you mean the tingil and ri pandan?

Reading a mantra across the sorsoran certainly seems appropriate in the context of Majahapit times. And the mantra om ganesha siwa om seems logical when a jenggot is present.
However, in many cases there is no jenggot. Can we assume that it would then be implied? Or possibly we should read the mantra from right to left (om siwa ganesha). As far as I know, a mantra must start with om, though not all mantras end with om.

My interpretation is based only on general knowledge of mantra, and no specific knowledge on how these were used in pre-Islamic Indonesia - so my interpretations may be very flawed.