funny seeing flounder scales's tail here, I think he used a lot of his techniques from my youtube video never really credited me for it but ok) I personally handsewn all scales on and the added a bit of silicone to the tips to prevent them from going anywhere and as extra strength. It definetly works very well to me! You can also try using the sewing machine to sew them on fast, I saw nymph_marielle doing that on instagram. I'm not sure how well that stays on tho