Just a quick reply-if the thread is being pulled to the top, the bobbin tension would be too loose--not too tight-- or the top tension too tight--not too loose.
As an embroider--on a commercial level now retired--I would never recommend a top stitch needle. A 75/11 needle is all that is needed for embroidery. If the design is running well it doesn't sound like you are pulling the quilt. In our machines we used a thinner thread on the bobbin as well. The underside of embroidery doesn't normally show. Hope this helps.
Wendy