Sorry, I haven't been around, been praying my thanks to God.
Anyway, your runner should be squared to the back that you previously cut. Use quilting rule and rotary cutter, cut off the strips even with the back and waslaaaa, your all squared up, or you can cut round ends, or pointed ends. The beauty of this is it's all quilted, just needs trimming and binding!
PM me Marmar if you have further questions.
Happy Quilting,
Sharon