If you are planning to use No. 8 pearl cotton am I correct in assuming you are going to do a type of 'big stitch' quilting? I think that would look very nice on a black background because it would give nice dimension. Cross-hatching is generally for a backgound effect. Sounds good to me. Perhaps a varigated thread would be distracting-it just depends on the design of your quilt. Please show us your project.