Is this an old notation?
Dy default I get
Which is best?
TIA.
I can’t say for sure if it’s an “old” notation, but it’s one I’ve never seen before; it may be an idiosyncratic notation used in a certain place or time. In any case, it would easily be missed or misread (we’re not accustomed to looking between notes on the same stem for important rhythmic information, and your lower example (the default, as you describe it) is absolutely the one to use.
Out of curiosity: what instrument is playing this?
My guess is Piano. And it looks like Percy Grainger’s woggle notation.
It is
Lemare, E.: In Missouri, from the suite In the West, op. 60, for organ [G. Schirmer, 1909]
@Janus
Would it be better to write
I would either have a tremolo (as per your second imagine in the original post) with tied notes, or, your latest image without tied notes.
They would sound the same but maybe the tied notes signify another instruments sustained note, and you wouldn’t necessarily have that “connection” without the ties.
As I said, they’d sound exactly the same.