I just did a quick google search and this website says your fabric should be 1/4 to 1/2" larger ALL around than you papers. So, if you are using the 1.25 sizzix die to cut your fabric, subtract 1/4-1/2" from all sides and that will tell you what size your papers should be. If you are using the sizzix die to cut you papers, add 1/4-1/2" to all sides to get the size to cut your fabric.
http://echinopsaster.blogspot.com/20...nted-blog.html