As a 95% handquilter I would use different colored thread for each color in the design or varigated thread. I would also never stitch in the Ditch when handquilting. Your quilt top is delightful. You did a great job. I have been quilitng for more than 40 years and my piecing isn't nearly that good. My favorite thing to do is white on white or preprinted "cheaters" cloth so I don't have to worry about my seams and corners etc.