The chain is one of the parts that cannot be "almost" the right size, With the amount of force/torque that the chain receives, its vital that it synch with the sprockets, even if you are off by a couple of mm, all that force would ride/jump closer to the tip of the tooth when it was about to release/clear in its travel. This would excessively wear your teeth down, risking a fracture.
If it were too tight, then you would be over-tensioning the chain during high force as it wraps around the tailside of the sprokets. The teeth wont move, neither will the dimension of the chain, something will give...i fear it would be the shaft connecting the transmission sprocket. I would make sure that they absorb all the S&H costs of your return of the chain for the correct size. THOR
