I don't think you want to trash any Squires. This is true for most games, but especially here. They are the only splitter, you want to be able to draw your deck with Council Room and then play as many Goons as possible. Trashing your Coppers that you have bought last turn with Forge or Count (obv you didn't buy them with Forge or Count, you are trashing them with Forge or Count) is also nice if you can do it. Even better if you can Haven a Squire every turn to make sure you always have one. There are just so many things that the extra Squires are useful for, and topdecking a Squire and trashing three junk cards is more effective at getting rid of junk than gaining a Copper, trashing a Squire and three junk cards.