I use this one:
http://shop.sew-classic.com/Low-Shan...foot-55417.htm
But mine is all metal. I've seen the all metal for sale somewhere but I can't remember where now. Works wonderfully. I drop the feed dogs, reduce the bobbin tension by 1/2 a turn and it fmq's beautifully. No need to change the top tension; as a matter of fact leaving the bobbin and increasing the top tension wasn't effective at all. Don't know why, but whatever makes the machine happy! Lol
Just need to figure out this speed control.