Forum:Spellcaster/counter Deck help?

Hello, I have been trying to edit my deck a lot recently and I was wondering if coming here, I could receive some pointers.

Spellcaster's Assault
As you can see my deck is a bit bulky and I am seeking some advice as to how to shorten it. I often havn't understood the concept of 40 card decks as I felt like it would be an easy victory if your best strategies are beaten at the turn of a card. I'm aiming for a sort of variety in my deck with Spellcasters as my most common monsters, I feel like this deck would normaly be prepared for several situations but it is still a bit too big. Any help would be greatly appreciated. If I could I would aim to add in two Magician's Valkyria, Dark Magician Girl and a set of Silent Magician's as well as a Dark Magic Curtain, maybe Thousand Knives, and one or two Crusader of Endymions once I can obtain the cards. (PS: I wasn't sure if there was another topic like this or a specific area, if so I'm sorry.)