In North America the German bow is just as used as the French. There is no real bias within orchestral auditions, all you have to focus on is playing to your best ability.
German bow is expected within Germany and Austria as all orchestra's within these countries only play German bow unless you're an immigrant. If you win a major orchestra audition within these countries using French bow you would be expected to switch within a certain amount of time.
Like most orchestra's, the conductor wants unity but it more so comes down to individual preference. In Germany/Austria they would want you to play the Dittersdorf Concerto the way they play it. They play very differently to that of those in the U.S, mainly because we might have 6-8 bassists in a section whereas they will usually have 8-12+.
I have no real knowledge of New England traditions, even if I did, it's irrelevant. There are German bow players in Curtis just as there are French bow players in Austria, all it comes down to is your playin! If you love German, play German and don't look back!
PS: There were overhand bows in the baroque viol period as well. Many period orchestra musicians are comfortable on both bows.
