Frances, when my machine beeps and stops sewing and the message says check thread or whatever I just wait a few seconds then I hit the pedal and continue to sew, it works. I just ignore the message and do not press OK to take the message off the screen till I'm finished.
I do not mark before sandwiching the quilt. I use a pounce with iron off chalk. If I don't have the right stencil, I will draw a design on rag vellum and stitch the design with an unthreaded 18/120 needle. It makes a great stencil and I get my brain in gear for the quilting.
For me, I prefer more improvizational type quilting. I like Patsy Thompson's method for free motion feathers. I just draw the spine and go from there.
Coast of South Carolina USA
Sewing/Quilting on my Viking Sapphire 870
Golden threads paper is nice, but you still might be picking out bits of paper from tight curves or corners.
What about a stencil? If you can't find one commercially available, you can "make your own" by printing up the design you want to use on heavy card stock, then stitching along the lines (without thread in the machine) using a heavy-duty needle. Then you can use a chalf pounce pad to transfer the design to your top.
I have finished the quilt "Scrappy Nine Patch" in Alex's book Machine Quilting. When I went to mark the quilt, I used the Plexiglass idea with the light underneth, however, I couldn't see the pattern through the fabric. So I marked it all on tissue paper and quilted it, but now I'm picking flecks of tissue paper out of the quilt. Does anybody have any better ideas of how to mark a commercial pattern to a quilt when you can't see through it?