The idea of six days not being literal is NOT supported by the bible:
Exodus 20:11 For [in] six days the LORD made heaven and earth, the sea, and all that in them [is], and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.
Exodus 34: 21 "For six days you may work, but on the seventh day you shall rest; on that day you must rest even during the seasons of plowing and harvesting.
Is Exodus 34:21 refering to six peroids? I don't think so!