  For a Minkowski centered convex compact set $K$ we define $\alpha(K)$ to be
the smallest possible factor to cover $K \cap (-K)$ by a rescalation of
$\mathrm{conv} (K\cup (-K))$ and give a complete description of the possible
values of $\alpha(K)$ in the planar case in dependence of the Minkowski
asymmetry of $K$. As a side product, we show that, if the asymmetry of $K$ is
greater than the golden ratio, the boundary of $K$ intersects the boundary of
its negative $-K$ always in exactly 6 points. As an application, we derive
bounds for the diameter-width-ratio for pseudo-complete and complete sets,
again in dependence of the Minkowski asymmetry of the convex bodies, tightening
those depending solely on the dimension given in a recent result of Richter
[10].
