I think you have to go with the attacking option. I also think the left-armer is a good idea as Strauss struggled against Pathan in India. You can't pick your team for the 1st test assuming that someone like McGrath won't bowl well and keep it tight, or that Warne won't be able to bowl long spells and tie up an end whilst taking wickets. So with that in mind you have to go with a Tait or Johnson, and I think the left-armer option offers your attack more variation. Not to mention that Johnson has done well up against KP in their few encounters so far.
That means you'll have McGrath, Lee, Johnson, Watson and Warne as your frontline bowlers, and to be honest that's a pretty good attack, if they bowl well easily good enough to win the 1st test. Compared to Harmison, Hoggard, Anderson, Flintoff and Panesar/Giles, there isn't too much difference, except the Australian attack has more variation, more pace, and a better spin bowling option. So all round if they play to their ability you will stand a good chance.