Beautiful quilt. Try pinning the purples to a side and step back or look through a reducing glass to see what it will look like. Personally I'd use the blue...but then again I am a blue person.
I use a front door peephole glass (available at Home Depot/hardware store) as a reducing glass. They look like little telescopes, are cheap and do the trick. I carry one when I go fabric shopping so I can see what my fabric will look like put together, from a distance.
Hope this helps.
Anita