I know I am reviving an older topic but there was so much good information in this and it would seem that others looking for answers to this problem could continue to get good information from this post.
I have tried several of the suggestions here but I cant seem to eliminate the seams in the light bakes. I am almost at the point of just going to one large floor plane but I wanted to make it smaller modular pieces to help with the culling of objects as one moves through the space. Any thoughts?