If you have done puckers in the appliqué, I suggest you trapunto it before tufting. I trapunto by placing a piece of batt under my appliqué that is stitched to the top background, stitch just outside the appliqué edge with thread that matches the background. Once I have stitch all around, I cut away the excess batt from behind the top. When the top, batt and backing are sandwiched, this leaves a double batt under the appliqué. I outline stitch the appliqué again and this should give you enough for nice tufting.