If it had the same data center to rock ratio as earth, it would just end up being earth in the end, and earth doesn't seem to be wanting to stick to its equilibrium either right now
2 * pi * r^2 * L / (4 * pi * d) * (1 -a) = 4 * pi * r^2 * sigma * T^4
As you can see there are pi*r^2 on both sides of the equation, the surface area to cross section ratio of a sphere doesn't change as it gets bigger and so the equilibrium temperature doesn't change no matter how big the sphere is. (d is the distance to the Sun, nothing to do with the sphere itself).