i've done alot of stained glass applique and it seems like that technique would work just fine for your black areas/legs...
i have used 2 different techniques- one- i use my double needle- threaded with black- and do a straight stitch--this works IF the legs are 1/4" wide (or the width of the double needle)
i have also used a zigzag- since it was black on black i did not tighten it to a satin stitch just a zigzag that was the width of the pieces- so i did not have frayed/rough edges.
LOVE THE QUILT BLOCKS!!