This is just beautiful - I love the colors that you chose! I am just now cutting my fabric - following the same idea as you are. Keeping the size of the blocks the same as the throw, and adding more columns and rows as you suggested. Ideally I would have it be about 90" long, but we will see how it goes here. I don't think I will attempt the appliqué though - a little out of my reach.
Thank you for posting pictures - I'd love to see your finished quilt!