π cornerhorns throw a very uniform sound field throughout the room. Because of this, there isn't so much of a "sweet spot". It really sounds good throughout the room. However, stereo imaging is naturally best when you're equidistant between speakers.It sounds good anywhere within a 90° horizontal arc, which is everywhere in the room, but best within 60° (+/- 30° off-axis). You also want to be seated within a 40° vertical arc (+/- 20° off-axis) from the midhorn and tweeter. That's pretty easy, just be seated at least a couple feet back, in the center, between speakers.
Plans come with dimensions for the cabinets and schematic for the crossover. Tell me your E-Mail address and I'll send you the plans.