I'd be interested to see what the maths says about the pressures on the surface given the mass and size. Would the pressures be large enough to collapse the matter into something fluid like? If so, the whole collapses all too quickly into that black hole.
I'd also disagree about the statement about the gravity well. The gravity peaks at the surface  the exact centre has equal mass at equal distance in all directions and is thus in zerog!
Finally, the body can't be treated as a point mass at the centre when calculating surface gravity. That assumption requires a solid body of uniform density.
The distance to each place varies and the pull exerted is dependent on the inverse of the square of that distance. So that portion of mass directly below a point is twice the distance away that a point mass at the centre would be...Thus it has only 1/4 of the effect.
