We did it mid-March? Managed half of the ridge, then we got a white out and had to bail. Very wild & pristine area.
Date approximate - was around then. A very impressive and complex mountain. One day I shall go back in winter.
Colin & I formed a cunning plan to do the whole An Teallach ridge over 2 days. We started on the 14th and finished on the 16th with an ascent of Sail Mhor on the rest day between.
The weather was excellent and we enjoyed the whole experience.