As already noted, start by assuming that it is DFC, and in an equilateral triangle with the speaker stacks. But, that has to be qualified by actually looking at the positioning of the stacks: are they tilted downward, in toward the center, arrayed in several directions. If there is house music playing when you get there, then do the walk around as suggested. In general, where you can hear things sound best, so will your mics, particularly if you can fly them above head level.