Which Tank Was Your First MOE

As I bounce around with my tanks more often than not, the possibility of gaining an MOE is questionable because if I play with one tank straight thru I suffer more losses than anything ... and manage to do less work. How long did you have grind in any one tank to get your first MOE? And which tank was it? Ironically I finally got my WN8 up to 999 yesterday, but it dropped ... I've had some recent high damage battles including my first over 4K match ...