I bought the second chapel with my horrid turn 3 (CCEEE) in hopes to catch up with the thinning.
Look at it this way: Your next hand will be either
5 coppers -> buy the Wharf.
Chapel and 4 Coppers - yay, you get to trash 4 cards. Money density is not a problem because you already have an Ironworks that can get you treasure cards.
Ironworks and 4 Coppers -> Ironworks your Talisman and buy the Wharf.
Chapel, Ironworks and 3 Coppers, as in game -> you can Ironworks a second Ironworks and still trash 3 cards.
You don't need to trash that quickly. You have Wharf, after all. And *it won't really even work anyway* - now you have to get lucky to not have the two Chapels collide initially (*and* not draw them dead as you point out), and then the extra Chapel is an extra dead card that you *do* want to collide later (or keep for Vineyards I guess).
Also, did you consider picking up Jester later at all? He's advertised an intent to build a deck that's mostly high-value treasures and green cards. That's a great target. Yeah, you won't be able to power up your Vineyards directly, but...