Re: Potato Rule doesn't apply
I think Version1.0's point is that when things get big enough gravity tends to make them spherical no matter what shape they were originally. There is a minimum size/mass for this to happen.
For rocky/metallic bodies this size is somewhere between Vesta and Ceres.
For icy bodies this happens at a smaller mass (presumably bigger than Ultima Thule.)
For something made out of nickel and iron this size will be bigger than Ceres.
But if they spin fast enough (like Saturn) they start to bulge out at the equator and stop being spherical.