I am unable to assume that the lack of uniformity in the charging situation is somehow analogous to the steady state situation. They are completely different. In the charging situation, there is a changing drift velocity. Such is not the case in the steady state situation.
Let's be a little more direct here: To what plane does the electron bulk flow actually contract towards as a result of the bulk's relative velocity with respect to the rest frame of the positive charges?
For our sakes, let's assume that the observer is positioned between the 4th and 5th + charges and that the - charges are migrating to the right.