This drawing poses an interesting question about the readability of what I call a "free-floating" minus sign. Without a nearby point of reference, (36) can look like (14) or (25). [Even if you were using the UEB symbols, which you should not do in a Nemeth transcription, (5, 36) is also ambiguous.] In the context of the subject matter, it will probably be clear that this is a minus sign. If you would like more clarity, the only solution I can find in our reference books is to borrow the spatial "minus sign within a circle" symbol from the Chemistry Code (3.4.2) which is used in spatial diagrams for exactly this purpose--to give clarity to the symbol. If you use this symbol (1246, 14, 36) I would also use the symbol for "plus sign within a circle" (1246, 14, 346). You can define these two symbols in a TN preceding the diagram.
I'm curious to know what you think about this idea. We are thinking outside the box!