Distance from pulley to pulley

I am building my first eskate with the MBS atom 95x with a version of there rockstar hubs on it. I am using the trucks that came on it and i bought a motor mount from ebay i found on here. My converns are about how long the mounts are and if the distance in between the wheel pulley and the drive pulley matters at all? By the looks of it they will be very close to each other.

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