I believe the wishing wells should be gained on this board, otherwise you lose. The thing is that you both chose the wrong card to trash here. Wishing wells work well only when their density in your deck is very high, or when there are 2 cards in the deck. This means that you should clearly prefer the trading post as it gets out of the way 2 cards and always give you the same card. Ideally you end up with wishing wells and silvers here before you green. There are other cards of course to consider here and maybe a late upgrade to turn the post into a gold and the ironworks in a duchy is good, depending on how fast your deck cycles, or in other words on how many wells you have and how well they work. But you should expect that after 3 provinces your deck will not cycle good if you split the wells. With all the wells and just silvers, this should not be a problem though.