You never mentioned the bobbin tension. You need to loosen the bobbin tension as much as possible before adjusting the top tension. For high speed machines, looser is better because thread stops breaking. If bobbin tension is loose, top tension can also be loose to get a balanced stitch.
A larger needle can help with breaking thread too. Many frame quilters use a size 18 needle.
But, watch the video! I believe his recommendations apply to all machines used for frame quilting. I could not get my bobbin tension as loose as he demonstrates; the screw in my bobbin case fell out first! However, I did make sure it was as loose as I could get it and still keep the screw in.