Where do I position 4 speakers for 3D stereo sound

My room is 22-15-8 feet. I have a pair of K-horns, and a pair of Lascalas. The K-horns are along the short wall facing outward using four foot false walls. The Lascalas are in the rear to provide a 3D effect. Both pairs are using separate Mark Levinson 334 amps. I am aware that these speakers are designed to be played loudly. However, when played at a low volume, they can create sound effortlessly, and without any distortion at all. My problem is how far back from the K-horns should the sweetspot be positioned,and where should the rear speakers be positioned
to provide the best 3D sound? If the sweetspot is ten feet from the K-horns, then all speakers will be equal distanced from the sweetspot. But is ten feet too close to the front speakers? If the sweetspot is moved back, will I be too close to the back speakers creating phase problems? In that case, should the rear speakers be reflected off the back wall, or side wall? With this in mind, the high frequencies from the tweeters will be lost? Does anybody have any ideas about this problem?