i prefer quilts with illusions to have more simple quilting designs so that it doesn't over power the illusion and cause the eye to focus on the quilting instead of the piecing illusion.
i've seen many LA ruin a great illusion by not following the illusion pattern.
here's a link to a bargello on the board that was quilting perfectly to maintain the integrity of the illusion
http://www.quiltingboard.com/t-108229-1.htm#2785737
if you google bargello and study the quilting designs you might get some ideas that you would be able to do on your quilt.