As long as an opponent controls more lands than you when the Knight enters the battlefield, you can search for a Plains and put it onto the battlefield
Its not likely to make it into your zombie typal decks, which arent red that often anyway, but this card puts in exceptional work in a Feather, the Redeemed deck, for example
For the most part, I dont think it matters, as basically, every blue deck should be playing both
Breeches drives the stealing aspect of this Commander deck, but Malcolm is a useful ramp enabler that synergizes very well with Breeches, forming a perfect pairing of the two
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Overall: GW is going to be a skill-testing archetype, since youll need to properly evaluate when to cast your Adventures and when to just cast the creature halves immediately