We actually need a Scots lawyer on here to explain fully. I'm not one.
Until fairly recently, I mistakenly thought that 'not proven' meant 'probably guilty, but we don't have enough evidence'. Apparently, that's not the case in spite of what Wkipedia says, but I don't have the legal background that would allow me to give a full explanation.
Some legal commentators have said that the rule changes will actually make it more difficult to obtain a 'guilty' verdict, since a larger majority is now required.
Anyway, here's a very full account of the possible nuances. You really do need to read to the end for this one. (This was written before the change in law came into force.)
www.cambridge.org/core/journals/legal-theory/article/threeverdict-problem/151D1F08B6E29CC302BC084ECA2A0C12