depending on the size of the orchestra, you would need mics and a recording chain with fairly low noise since in approach B you would add the electronic properties and the specific noise of your omni pair several times at equal levels. That means +3dB of noise for every member of the orchestra you record individually if, as I assume you would, you add equal levels. This is different from the main/spot technique where you have lots of mics but you don't add equal levels with the spots well below the main level.
You would also need pretty low bleed click track headphones since any bleed audible in the room will add by as much as 6 dB if you're unlucky.
These issues will not apply if the music is really loud most of the time.
Still, if you use inferior mics their uneven frequency response will add in an unpleasant way.
It is probably needless to say that the way any group of musicians will play together in one room is much different from single guys playing to a click or guide track. This weighs far more than all the technical issues involved.