I'm so sorry about your Dad. There's nothing so special as being daddy's little girl. I dread the day my 83 year old dad leaves this earth to join Jesus and my mom. (I can't even type this without a big lump in my throat.)Hugs and prayers to you. I'm sure that making this quilt from his shirts is a bittersweet project. I plan to do the same someday, and since I now do his laundry every week, and he is a dress-shirt kind of man for the most part, I handle his clothes a lot.
But to your question, the white sashing is perfect. It lets all the colors and patterns take the spotlight. The other one is not a color that's in any of the fabrics that I see, so it doesn't do anything for the pieces. What are you thinking for binding? Scrappy? Dark Grey? Navy?