For your piping color confirm, in fact I think it is OK. We could stitch the inside and then turn the bag over but this may bring some wrinkles to the bag surface since it is laminated instead of mere non woven. And the cost will be higher at the same time like +USD0.04/pc. And even if we do stitch inside, the front white color will be always against the gusset black color when you look at the bag.