#19 or #39 Small stitches for small pieces larger stitches for larger pieces.
I wouldn't use the one with dash stitches IMHO
Make up a little sample with a large and small applique on it. Try different lengths and widths of stitches and see what you like the best.
It also helps to practice the stitches on a sample to get used to manuevering/stitching the applique :wink: :D:D:D