I haven't read thru all the comments, (apologize for that now) but just wanted to mention remember with 108" fabric your're getting 3 yards(108") in width for one yard of fabric so for 3 yard by 3 yard piece (108" x 108") and about 51.00 you are getting a backing you would almost pay that or more for enough 44" to make the backing.
I have mixed both fabrics and have had no problem with doing so. I did prewash all the fabrics though.
Judy