I'll put my vote in for Spirocore Solo strings. They are durable and project very well. While a transcribed part might work okay with piano accompaniment, I think that using solo strings/tuning is necessary when playing with an orchestra, IMO. To me, it helps projection, clarity and solo strings are made... to solo on i.e. the lighter gauge helps fingering. Heres a video of me with the BSO, it was taken from the top tier, and, more obviously, to the side so the little condenser mic isn't getting most of the sound but I think my volume was sufficient...
http://www.youtube.com/watch?v=OhIo7k9eBks
Edicson Ruiz also uses Spiros for his solo stuff
http://www.youtube.com/user/doublebassVenezuela
And Furtok uses Spirocores with a Pirastro Permanent A string.
http://www.youtube.com/watch?v=1WMO0nJRWAM
And I think that Nate West is using Original Flatchromes here.
http://www.youtube.com/watch?v=D_42sgcVW3M
Hope this helps,
Andrew