Consider first the nature recording gold standard of Sennheiser MS pair. Less noise, fits conveniently in one Rycote Zeppelin, no rear lobe, can handle high humidity.
While Sanken CS3e is maybe the best short shotgun there is (I have one for video work), if a stereo pair of those were better than the Senn MS system, people would be using them. They are not, that I have ever heard. That should tell you something.
One slightly cheaper and more convenient solution might be Pearl MSH series stereo mics, same noise figures as Sanken (16/15 dBA). Pearl