Your quilt is beautiful with or without wavy borders! I'm sure everyone here has had those pieces which we just wanted to finish at any cost. Since the quilt is for you only, I agree with your decision to just let it go. If it were going to be a gift I'm sure you'd feel differently and tear it apart.
I've learned something new here today as well---the 1/2 inch deduction on the measurement is something I had never heard. And I love the "saggy bottom" theory!
Quilt away and post another pic when you're finished..