measure the panel first
Just make sure whatever you do that the blocks you use will match within the size of the panel. Once I didn't check my panel size and I had already cut the fabric that I wanted to use and I had a heck of a time adjusting to the size of the panel. So now I always check the size of the panel and adjust my block size from there.
Hope you post a photo of the finished quilt. I love seeing what others do with their panels.
Have a great day quilting