if a peice of furniture takes up more than one tile when placed in the player's home does the feng shui generated by placing it acording to it's colors get multiplied by the amount of tiles it takes up (if all the tiles are assoiated with that color)? I'm trying to figure out if I would get more points by placing say a two tile couch that has two yellows or two one tile items that one has two yellows and the other has one yellow and other such things like that.

I don't believe that the feng shui is graded by how many pieces of furniture you have, just that the available spaces are the correct color. Keep in mind that when your room is completely upgraded, you have more area that you can use. I found that the watermelon table put in the lower right corner counted for red and green. I did a fruit themed room and by pacing the furniture in the correct places got a perfect score.