I remember Ricky, in one of the shows, demonstrated the effect different weights of thread had on the blanket stitch's look. He likes to have it been seen, so uses a triple blanket stitch... it over stitches each stitch 3 times to give that heavy look. An alternative to that is to use heavier thread and a single blanket stitch.
As Rita suggests, you'd need to do a test patch with some scraps to see how it looks and if you like that. And try a 50 wt in the bobbin, so it's thinner and won't show on top.
Let us know what your tests show...