You can always make EQ adjustments later if necessary. If the possition you are in makes that necessary, you probably will need to do so regarless of which pattern you choose, and it will be more a questions of dialing in howmuch adjustment and where. The choice of pattern may hinge more on what kind of crowd you expect and how you need to manage that. I'd go omnis, but I'm biased, usually get good crowds, and almost always EQ it anyway.
Mmmm jazz jusion. If this is the show I think it is, an important thing is clarity of the piano, clarity of the piano, clarity of the piano.