You should be able to tell from looking at the interfacing - you can see the placement lines.
I vaguely remember 2.5"x 5.5"
Call Quiltsmart - they're lovely to deal with.
Phone: 952.368.3000 (Minnesota)
Those measurements kind of make sense - the 6x6 is 20" larger than the 4x4 LS.
I made four Lone Stars using this method.
It take all the hassle out of making the sections.
I did NOT put it together the way the instructions said though, as I wanted a much more interesting look.
So I put them together like a traditional LS, y-seams and all.
Here's one:
http://www.quiltingboard.com/t-127778-1.htm#3397137