Hi Charles,
I was waiting for some of our Indonesian forumites to comment your ceremonial knife before responding. But because it's late now in Indonesia I guess they will respond tomorrow instead?
Below is a related Balinese ceremonial knife (see pict) that is not as beautiful as yours but double the size (If you can't compete with good looks...).
This isn't pictured in any reference books that I am aware of so I have made some research, that I hope to get confirmed or corrected by other forumites, on the ceremonial use of this knife ( I guess the use is the same for yours?)
When a high caste Balinese dies there is a procession where the corpse is carried on a high, decorated, construction when travelling to the temple. In front of the procession two "soul guards" are walking with one ceremonial weapon each. The one at the left is carrying a Tombak in both his hands held at his head level. The one at the right is carrying a ceremonial knife like mine (and probably like yours?) at his head level, also with both hands.
The hilt of the knife is connected with the corpse by a long textile ribbon.
I hope I got this correct and look forward for the more knowledgeable from the cultures response.
Michael