I have mixed creams and white tonals together in one quilt. I'm quite pleased with it. But like others have said, just do what your heart is telling you after you play around and put fabrics next to each other on a design wall or cutting table - or on the floor and stand back. Depends on the pattern and size of the piece, right?
http://www.quiltingboard.com/t-81391-1.htm
And Hinterland, I think your quilt is stunning!!!