I agree with 19 or 39, probably 39. I did a machine applique workshop with Michele Hill at Barrossa Quilt Shop here in Sth Aust. she is a William Morris expert (her work is beautiful and she has a couple of published books) she uses a Pfaff machine, I have a Janome, and the stitch she advised looks like your 39. Stitch settings were Pressure - 2, Length - 2.00, Width 2.00. If I remember rightly I think I made the sitches a bit bigger for larger pieces. It took a fair bit of practice and personally I use Satin Stitch more often and especially when there is a lot of small pieces, I find it easier to manipulate. I love hand applique also. Have fun and enjoy! Jen Moore