In the end, Van schooled me in the game though the scores looked closer than it actually was. I lost the record sheet but it was in the region of: Van 126, Me 114, Dirk 93. I struggled to pay exact to reap the extra actions while Van seemed to make those buys effortlessly. On hindsight, I was perhaps a little too eager on a couple of buys and should have bid my time and accumulated currency. But the key to Van's success was her external wall. At the very first scoring round, she already managed a 14 for her external wall. I managed a miserly 4. While she wasn't able to further expand her wall, 3 rounds of 14 was sufficient to give her an unassailable lead which I never got close to. In fact, I was almost on the verge of an embarrassing loss to Dirk but my wall scoring on the last turn prevailed in giving me a clear advantage.
The 2-player rules allow players to purchase tiles on behalf of Dirk. In my 2 games so far, no one has ever utilized this rule since on the surface it makes no sense to do so when the tiles could be added to your own hand. However, I do see opportunities where you are so out of the running of a certain building that you can add to Dirk's hand so as to reduce your opponent's score. Furthermore, it may allow you to clear a tile which doesn't fit nicely into your estate. Will look out for opportunities next time round.