Well. I don’t have extra matching centers to play with. But I’ve spent countless with speaker placement and my laser pointer to balance 2ch imaging and soundstage with the added center speaker in a multichannel system, for one really great sounding front end of my room, that images very well(considering its pedestrian cost). In fact, the front and back of the room image so well between each other, it just creates one big surround bubble.
So, since we’ve got you typing, why don’t you accurately describe what the “improvements” are. If I, or you get confused, one will just have to ask for clarification. Obviously that’s not too hard.