It would be better to use 3DGS physics.

1. 3DGS is inbuit and there is no overhead in setting the level.
2. Sphere and Box collission work best in many cases. There is limitation in Newton where one cant even have a model as a geometry as this has not been implemented for c-script. So there is only box, sphere, and wmb objects available in Newton.
3. You can easily disable and relocate your objects to new locations and again re-enable physics.