Regarding the match versus the Landstill, I knew what he was playing beforehand from observing him from round 5.

I was not aware of not being able to sideboard if a game hasn't been played out though.  

As for the match versus Oath, he could have just tapped the Forbidden Orchard in response to my stripping it, and I wanted the opportunity to keep as many permenants as possible to sack to the Smokestack just in case.

Finally, with the Trinisphere issue, on the play I usually side them out for the CoTV's.  I think this occured versus Parfait and Fish.  Chalice for 2 obviously hurts both decks, so I decided to go that route.  Game 3 versus Fish I sided the Trinispheres back in, just for that "I win" factor, to paraphrase Dicemanx.

Shawn