I would also suggest a grey, Also would use something that is a thinner thread like So Fine or Bottom line. You can try it on making a quilt sandwich on scraps and see if you like it. I always use what works best with the top and then use something on the back, that is not going to show much if my tension is off a bit. It doesn't take much to throw tension off a bit to show the bobbin thread a bit on the top, like going over a thick seam, or around a tight curve, or simply going to fast. I also have used a sort of pastel, dusty color on the top if there is a lot of white depending on what other colors I have used. Like a very pale yellow, rose, green, or blue. Often those do look fine on the white if using a thinner thread and do not look so stark on the darker colors like white would.