I'd also recommend against Blumlein. As much as I love the imaging, it always disappoints me when it comes to the bass.
IMO, spaced omnis would be ideal if you can get in a couple practice runs where you record from various locations and spacing and see what sounds best on playback. Of course things will change a bit when the audience fills up, if the final recording will be made at a live performance. Whereas personally if I was flying blind, I'd run a Jecklin disc where the live sound was best to my ears.