I have tried so many different gimics for half sqs. Even TA Da fusible interfacing pre printed with all sizes. They made a great pattern to transfer to paper. Then go thru the tearing off bit. Did not want to purchase more fusible.
Watch this video especially the second half.
http://quiltinaday.com/television/vi...lesquareup.asp
I make many half square and quarter sq with it and they come out perfect every time. All sizes. You can get the ruler at Joanns with a coupon so it is very reasonable. The ruler comes with instructions for which size squares to cut to make 8 at a time.