It was a lot easier when I only had to distinguish between tigers and dugites (another Pseudonaja). I guess it doesn't really matter if you're going to get polyvalent antivenom whether you correctly realize you got bitten by an EB or taipan (tooth marks might also let you tell), but it was always fascinating to figure out which thing I'd gotten uncomfortably close to stepping on by accident. (But it was always EBs that I almost stepped on...they're way more common. I only ever saw one taipan I was sure about, and at a distance at that.) If they have the courtesy to have fairly dark coloration, the light jaw of the taipan usually gives it away. The lighter ones are hard to tell. Lucky for you in the Riverina you didn't have to worry about discriminating between them; I don't think coastal taipans get that far south.