Dont get me wrong the covers look great and Im not saying that your just throwing these together in 15 minutes. But Id still say an extra 5 minutes on each is all that would be needed to clean up the little bits of dust that are left with a few simple clicks with the spot healer (assuming your using PS). Id imagine that had these gone through tiktektak first, he would of said the same thing.
Not trying to bring your work down or anything. And I know what you mean by the scans not beeing the greatest to work with as Ive thrown a few together myself from the same source. Not the best scanner unfortunetly, or just not the greatest scan settings...