This is the machine that Leah Day uses in her 365 days of FMQ designs. She uses Isacord for her quilting and I believe it is poly. She recommends the same thread for top and bottom thread and she sells and promotes those washers for your bobbins. Had never heard of them before that.
Do you all love your Jukis? I've struggled with my Kenmore doing FMQ and am thinking of either buying a Husqvarna Mega Quilter or a Juki 98. Any advice?