I know what you mean by all the thread you go through with stippling. I have recently purchased some wonderful thread from
www.connnectingthreads.com, you get a lot for your money and it's very good quality, 100% egyptian cotton. I'm new to quilting as well and because I don't have a lot of experience with stippling, I always use thread that will blend in with the material that way my mistakes don't stand out. When I run out of bobbin thread I just cut the loose threads and try to start a few stitches back and trace over where I ran out at and keep going. It seems to work well for me as long as I bring the bottom thread up to the top of my quilt and position my needle into an existing stitch. I hope that makes since.