Frankly speaking, if you have purchased two EP500s, I wouldn't worry that much about location as long as they are not located directly opposite each other on opposing walls. As with many of us, the sub crawl has limitations in that what might sound the best to your ears at a particular location in the room might not necessarily be practical for placement. Two subs of the EP500s caliber will mitigate many of the issues you are concerned about. You just have to make sure phase and volume levels are set properly.
I have FOUR subs and because of those space limitations in my A/V room, I had to place one in each corner slightly behind each one of my Left/Right Main speakers. The other two are behind me on opposite walls. When all is said done the sound turned out great. I never did the sub crawl, there is just too much furniture in the room to worry about all that. As I stated, once you set your phase and volume levels correctly, everything should work out fine.
