I have the juki 2000 on a frame and I just did a queen size the owner wanted extra long so it's 110" long. The throat space was still fine allowing me about 4"in work space o nthe final row. Thats using cotton batting. On the thread issue I have had a terrible time with CT thread breakage. Just my opinion. But use an 18 topstitch needle and you may get better results. I switched to poly thread from metroemb.com