No it would definitely have to be wider than 39". A twin BED is only 39" wide. When I make a twin quilt, it is about 60" wide, allowing about 10" drop on each side. If you want a larger throw, I would make it at least 48" x80'. So, you would need (6 blocks across x 8 blocks down) 48 blocks.
If you go by the charm pack size (5 inch squares) you should get 8 squares out of one width of the fabric, so you would need 6 widths to cut 48 squares. If you are using 4 different fabrics, a yard of each should suffice. But that does not include binding fabric.
I just saw a cute twist on D4P at
http://round22.blogspot.ca/2012/07/d...ith-twist.html and at the end she gave the measurements needed for the original blocks which I found very helpful.
Hope you post a pic of project.