Your closer, those darker spots are left over finish. Keep chipping away and you should be there shortly. I can tell you from experience that the smallest left over factory finish will gleam when you spray it down again. Be sure to get your string grooves to, they will have string wax and finish in them. I use my palm sander and 400 grit, most will tell you Im crazy and probably wrong, but I have some sweet refinished bows that will argue that. Have fun!