Patchwork borders are easier if the numbers for the Width and Length work together.
Example: Trim the panel length to 40.5 inches and use 4.5 inch squares. Remember to calculate for seam allowances.
Using the example of 40 Length, you can use other numbers 5, 8,10, etc
Trim the width so you can use a square size that works with the Length.Be sure the Width and Length sizes work together.
You can add a small trim border around a panel to make the numbers work for patchwork borders.