This will depend on how many fabrics and the width of the strips you plan to use. You can also do this with paper piecing, it should keep your blocks square. I find a king size might take around 13 yds, especially as you have so many seams. You need to have half of light colours, and half dark. If you do not need each block to be identical the pieces can be alternated, otherwise you will need more of some fabrics and less of others.