At risk of being shot down in forum flames.. I'd at least be checking with Jabiru that the 600Kg Fwd limit is not a typo in the POH. If I were a fit trim solo pilot who hadn't have a big breakfast, and found myself in an 'out of fuel' scenario, from my calcs I'd want to see Fwd COG limit not more than 195mm (19.7% MAC) in order to be able to land slowly and safely. I don't know the Jab, and am working from info in POH V4 Feb 20 and guessed the fuel arm, The thread is very interesting, and whatever the answer is, it's a good spot, a great question and a good exercise to go through anyway.