As per above, the only reliable way to have any leg room and minimise the risk of crushed knee caps is to pay for exit row seats or buy a PE seat. Of course, you might find other airlines offer PE or Biz at less cost than QF but that might mean going via the West Pacific or SE Asia - an option I would certainly consider especially if an overnight break is desired. Another option is to go via HNL - plenty of options this way including JQ and their LCC style “Business ”.