Ttowntony, FWIW I've a pair of the Signature Systems (1 piece) in route. My room is of a similar size to yours and I am presently using dynamic speakers with about the same frequency response as the Linbrooks. Mine fire down the length of the room and I have them close to the side walls and toed in so the axis of the speakers crosses in front of me - that way I have no 1st reflection issues from the side walls. My speakers are front ported but I'm still unable to get them much closer to the back wall than 3 feet (from the rear of the speaker) without elevating the bass too much. I'm assuming that the bass of the Sig system will be much the same.
You might want to consider the Linbrook stand mounted which might benefit a bit from rear wall reinforcement.
You might want to consider the Linbrook stand mounted which might benefit a bit from rear wall reinforcement.