Modern convention on this cello passage

[czoller]

Hello, all. I'm wondering if anyone can confirm if the cello passage (in bass clef) appearing in a manuscript (1.png) should be notated as in the typeset screenshot (2.png). I'm honestly not sure how this is expected to be played especially the "sul D" passage and so I would appreciate a brief explanation to a non-string-player.

[John Ruggero]

What clef are we in?

[czoller]

Bass clef, sorry.

[David Ward]

My uncertain interpretation (I learnt the cello to Grade VIII in my 1950s adolescence, although I became a trombonist): first pair, G as an octave harmonic plus D on open D string; next three pairs A, B, A on the D string, the D's all on the G string. However, I'm not certain, so a currently active cellist should be better informed. In any case, I suspect that this may not be the clearest notation for what is required.