Hi there aus*jen
I have transcribed many passenger lists over many years. I am aware that shipping arriving into NSW (so not South Australia) often lodged two or more passenger lists from the same era as your SA enquiry. From memory, at least one was in the mess order, ie in the order of groups who messed together, while the other may have been in the order of tickets issued/cabin class, second class, etc down to steerage. I think where there was a third list, it was in surname order.
I am somewhat confused by your comment about seeking an unbiased view. If this were my family, I agree that it would be sensible to consider submitting to the decipher board, but the views I would be seeking would be those of RChatters with a deep knowledge of and experience with South Australian passenger list transcriptions, so I would be seeking a disinterested view.
As I have no real experience in transcribing SA passenger lists, but I believe I am competent in transcribing longhand from that era, I would consider I could offer an unbiased view. However, clearly I cannot offer a disinterested view as I do not have a deep knowledge of how the SA passenger lists were compiled or transcribed.
ADD
Re the need to be always right ... I agree, when researching our own family history each of us is responsible for setting our own standards of proof to work towards. BUT ... surely when posting on the open forum that is RChat, it is also just as important to recognise that the search for evidence in official/disinterested records is paramount, and so rather than seek out a particular primary source record it is better to seek out several primary records to compare and validate the information to give confidence to the quest so that when you are ready to share your family history research with others, they can appreciate the process underlying your validated research?
JM