The engine is by far the right call here, but I do not like opening Potion. Against double Masq, I would have gone for Masq/Talisman, to load up on Heralds faster, add Wharf on first two $5s for the +buy and speed (if they come fast, otherwise, you may even do with just one Wharf), and then Cartographer. If he goes BM, adding Familiar later is better. He will be playing a single terminal, and have a hard time lining up Masq with Curses. Moreover, even if he does send some Curses back, each Masq played is a non-Wharf turn, and you will send the Curses back to him faster anyway with your own Masq.
Notice that Masq/Talisman is good against BM, because you do not want the earlier Cursing as bad, and it is also good for a mirror, because winning the Herald split is important, and later you can use it for a double-Potion turn, or even get double Hermits/Masqs to pump up Vineyards when the deck is consistent enough.