You will have to remove at least 4 Watcher's from the deck, making it 28. The rules state you cannot have more than 4 copies of any card, and that includes unique cards.
I am talking about adding a Gollum package to your deck so you get threats and some easy Shadow wounding.
Evil Smelling Fens means all the sites will be
Marsh which you need, plus its secondary ability could start a nice Tentacle swarm.
I assume your deck is designed which cards you have in real life, and which ones you are yet to have...?