I use my 15-91 exclusively for quilting. I have an 'Alphasew free motion guide foot-P60410' for FMQ, and an 'Alphasew P60400" walking foot. I found that I had to remove the thread cutter from the presser bar for them to fit well but without the cutter they fit just fine. I'm pretty sure that I got them from
www.sew-classic.com. Do let us know how things work out.