Performance difference between small part with large SpecialMesh scale and large part with small scale?

Hey guys. I’m trying to add some water underneath my map, and since the largest size a part can be is 2048x2048, I made the part that size and then added a SpecialMesh to it and set the scale to 2x1x2, which then makes the size of the part 4096x1x4096. The difference is that the extra 2048x2048 that is added seems to not be recognized by the physics engine and is non-collidable. With that said, I’m wondering if a part with a size of 204.8x204.8 and a SpecialMesh scale of 20x1x20 would be better or even make a difference at all in terms of performance.

Thanks.