Speaker placement along the long wall

Does anyone have any experience with speaker placement along the long wall? My room is 15'Lx12W. The rear of the room has a 6' wide opening into the dining room. This allows me to seat in between the two rooms (about 10' from the speaker right now), though it remains domestically unpopular. I'm considering relinquishing the space between the two rooms by moving the speakers along the 15' wall. The only problem is that I'll have about 8' from the chair to the new front wall, thus forcing me into near-field listening. My speakers are sealed box design(Hales Rev3). I'm wondering, before I attempt to re-arrange the living room, how close to the rear wall can these speakers be placed with minimal change in sound quality or any other pros&cons.

Responses are much appreciated.