What an absolutely lovely job you did on the quilt -- it looks wonderful! You should feel very proud!
Mom-6's idea is what I would do, too - the ties belong on the back so as not to take away from the front of the quilt. But I'd err on the side of caution and over-do the ties so you make sure the batting doesn't shift and bunch inside the quilt -- if it says quilt up to 4", I'd make sure those ties are at the very most, every 3", or even 2", and that they match the front of the quilt colors. Please show the finished product when you're all done - I can't wait to see the final product --- maybe on a clothesline?? Love it!