Being self taught I am not sure if I am doing it a right way or not but this is what works for me. I do a single knot in my thread. Starting I start from the top, inserting my needle about a 1/4 to 1/2" away from where my quilting line will start and leave enough room for my first stitch to be a back stitch. I pop my knot into the batting just like you and proceed to quilt. At the end I bring my needle to the backing. I then take a tiny back stitch only going through the backing. I then tie another single knot and take another tiny stitch, again only going through the backing but have the needle come out on this back stitch a good distance away and pop my ending knot in. Works well for me and because I use prints for my backs you can never see where I have stopped and started again. This technique would not work with a frame but with a lap hoop it is easy to flip over to see what is going on in the back.