I was talking to a friend who just got into the DMA program at Rutgers (where I did my undergrad) and I assumed he had been playing French bow forever because he sounds so good. Just the opposite! He learned on German, played that all through his undergrad and part of his Masters, then switched to French. He said after playing French for a month or two, it started to feel very natural and normal.
In his opinion, switching bows really isn't a big deal.
Also, my teacher told me that when Fred Zimmerman was trying to get into the NY Phil, he could play well enough on German bow, but at the time there was a very strong bias toward French bow in New York. So he learned French bow, got into the orchestra, then waited until he was tenured and started playing German bow again.
In his opinion, switching bows really isn't a big deal.
Also, my teacher told me that when Fred Zimmerman was trying to get into the NY Phil, he could play well enough on German bow, but at the time there was a very strong bias toward French bow in New York. So he learned French bow, got into the orchestra, then waited until he was tenured and started playing German bow again.