Point taken, but you've interpreted my message/language in a way I did not intend.
When I spoke of dilation, I did not mean to say that the ducts become larger of their own accord, I meant that, in the presence of huge amounts of magnesium, many tissues of the body have a tendency to 'relax' and thus, in the case of the bileducts, potentially permit the passage of larger traffic than might occur in the absence of such high levels of magnesium - Moritz often remarks that the Epsom Salts help 'relax the bileducts'.
In terms of strength of contraction, I've never subjectively noticed any difference with this, whether using or not using ES, and certainly no difference in end results.