If you want a 6.5" unfinished (6" finished) star, you would need a
centre square that's 3.5" unfinished (3" finished).
The flying geese for a 6.5" unfinished star block is 3.5" x 2" (unfinished)
3" x 1.5" (finished).
And you would need 4 squares for the corners. Cut at 2" squares
(1.5" square finished).
If you want to use your four patches as is then your star blocks
would finish at 8" (8.5" unfinished).
Hope this helps.