Great points all, thanks for taking the time to help me think this through. I just spent some time at the house and traced out the tables on the floor and I think it will work.
Steve, I know the seams will show on the tables, but I think that will be ok. It will be hard to find a tablecloth to cover the 60x90 configuration, but I'll see what I can do. I do provide a few nice tablecloths for more elegant dining (including a few I embroidered myself) but mostly my guests use bamboo placemats.
