I have had a lot of practice doing fusible, raw edge, button hole stitch applique in the last two years. It is the method I use most when making my postcards. I usually use matching thread for each individual applique piece but for this project I am using only black thread. I am using 50 wt Mettler as it seems to be just a tad heavier than most other threads. I really like using only black as outlines each piece and gives it all more definition. It sort of reminds me of the cross stitch projects I did many years ago, where you would outline everything. At each start and stop, I pull the top thread to the back and tie a double knot. It is very time consuming but I think it will help all that button hole stitch hold up over time.