Some of this sounds like deck construction. Why are you playing all these cards you need to play turn 1 along with Wasteland?
I agree with most which has been said in this thread, but I think this quote is particularly important. You've got to ask yourself why you're playing Wastelands in your deck. Is it to play a mana denial strategy? In some cases (combined with Stony Silence) it can be, but against Shops it's almost never correct to do so. And usually when playing a build like this it's not to deploy a mana denial strategy. It's often not even to make a tempo play but to hit critical lands; I usually see Wastelands as additional Strip Mines which many decks play as a one-of to hit an important land like Karakas, Tolarian Academy, Library of Alexandria or Cavern of Souls.
For what's it's worth, I wouldn't have Wasted in either scenario (and I 100% agree with BrassMan to let Thorn resolve in scenario 1).