I have made good progress on making the parts of my middle border. I wanted to make a 3" finished string border. To make it a bit easier for me, I used full sheets out of an old phone book.
Here is the front.
Then you have to square off the top and each of the sides. You don't have to square the bottom since it will be trimmed off as you work anyway.
After you square it up, you can chop it off into the size strip you need. I was able to trim my blocks into 3.5" strips
Here is my pile. I think I have enough! It went very quickly with this method. One issue I did have was with threads pulling away when I tore my newspaper off. To tackle this issue, I just ran the strips through my sewing machine, sewing a line about 1/8th inch away from the side edges prior to ripping off the paper foundations. It helped in more ways than one. These blocks can stretch and get all wonky on you, and sewing the edges helped to prevent any stretching when I was pressing with my iron. I think it will help too when it comes to sewing the border on the quilt. I will worry less about a lot of distortion.