Boxed In for a smile

4 blocks completed, 20 some odd to go for my quilt for Quilt for a Smile.  I'm still using this pattern and may make it a bit bigger.  I'm using some of my own fabric since the yellow and blue were a bit overwhelming for me and I needed some negative space to rest my eyes.  I am quite happy to make it bigger and supplement with the Kona Snow.  I am mildly curious if anyone else is adding some solids for sashing, what they are using for binding, as well as what they are using for backing.  The strips are pieced and cut and now it is just a matter of assembling everything.  I'm not sure about a border around the outside or what color for binding.