Hello Chris and welcome to the board. Love your quilt. Given the modern feel of it, I would recommend straight line matchstick quilting, no circles just very narrowly spaced lines, you could even make them a bit randomly spaced, like some 1/4" apart, some 1/8" apart and some a little more than 1/4" apart. if you google images of "matchstick quilting" you will see loads of examples. This could easily be done on your domestic machine with a walking foot. The effect of the matchstick quilting will give an added element of texture without detracting from the piecing. I would use a fine neutral thread like Wonderfil's Invisifil or silk to do this.