I remember the Irish coach said after playing Iran that he chose to play the home leg 1st and then the away leg after, He based this after watching the Iran/Australia play offs.They won the home game 2-0 and lost 1-0 in Tehran.
When was that? Irish is Irish, you should look at the opposite.

To put the record straight . . . . the Irish coach was wrong. Australia did not go to the World Cup from those matches, Iran did.
FYI. Australia played Iran in 1997 World Cup playoff match in which they played firstly in Tehran and then a week later in Australia. The first game in Iran was 1-1 draw and the second game was 2-2 which gave the Iranians the win by away goals, . . . . actually very late two goals to Iran, or otherwise it was really in the bag and then it was out of the bag in the last minutes.
But if you are to take an example of home and then away games, then history has been against Australia as each time they had their home game first. But they fair slightly better with the away game first and then home game in the second leg.
Consider their WC playoffs;
1973 neutral "playoff" venue in Hong Kong. Australia wins 1-0 against South Korea.(not quite a playoff as South Korea could not go through but the last counted pool game) leap frogging Iran to go to 1974 World Cup.
1993 won playoff against canada (CONCAF runner-up) on penalty shootout of 4-1 after a 3-3 aggregate. Away game in Canada then home game in Australia after two weeks time. After these playoffs, they went on another playoff against Diego Maradona's Argentina (group 1 runner-ups). They played home in Australia first and then away in Argentina in two weeks time. They drew at home 1-1 and then lost 0-1 in Argentina.
1997 see above. It was Terry Venables Oz team, they were leading 2-0 at home, second leg but then two late goals by iran sealed their fate on "almost but not quite" campaign.
2001 Australia played Uruguay. First leg was a home game which australia won 1-0. The second leg was the away game a week later in which they lost to Uruguay 3-0 giving a 1-3 aggregate.
2006 Australia played Uruguay. First leg was an away game which Uruguay won 1-0 and then 4 days later the second leg was a home game which Australia won 4-2 penalty shootout after a 1-0 win.
As you see, the home game and then away game has been a definite death trap for the Australians in 1993 vs Argentina and 2001 vs Uruguay, whereas the away game in the first leg and then the home game has been good in 1993 (penultimate playoffs) vs Canada and "should have been"in 1997 case vs Iran and a definite winner in 2005 vs Uruguay.
So better to have an away game and then home game especially if you have to go for a penalty shootout. Then in which case you need your home crowd support.
What I am worrying about is the one month gap to keep the team on match fitness. It is a bit unnerving allowing the Asian team a month to prepare since it is more than likely that their team are home-based professionals where as our team is not home-based and I am not sure of the players club commitments in that time of the year despite having those international windows.