Hi Erika,
WOW. What a lovely quilt. The colours are great. From experience if i have white in the top i usually go with a light backing. There are some realy ncie tone on tone creams you could have a look at. It not always that the colour comes through the batting but it takes the whiteness away from the white. If you get what i mean. Try some samples and see. Cheers. Quilter.