I also have that machine and while I haven't done much fmq at all, I did find playing with the three-hole guide made some difference, as did choosing a stronger thread. Still not perfect but I know most of that is my inexperience.

I've found my Juki seems to like Glide thread better than others for FMQ

I have the Brother 1500 PS I use the three hole bar for a thread guide, not for tension. I use one hole to guide the thread. The other holes are for specialty threads that need more help. A Brother tech told me this and said it wasn't addressed properly in the manual. Brother sure didn't spend any money on the manual I got with my machine. Very vague and basic.

Oh and never ever use a metal bobbin that has the open holes around it. Don't use plastic bobbins. That is true for most one stitch machines like Brother 1500 and Juki. A wrong bobbin will cause havoc and can cause damage. I know, I had my repaired twice by a dealer repairman that didn't know this and was blaming it on user error. A Juki tech said it was basic info every repairman should know.

the metal bobbin with the holes is for the high speed industrial, and if you are sewing fast it really helps to keep the bobbin cooler having the holes.

The tech told me the holes will cause the machine to damage the hook. I had to have two replaced because of using the holy bobbins. The repair guy kept saying I did something, well I did, I used the wrong bobbin but he didn't know or didn't bother to tell me. Cost a lot for repair and he got the fee twice. The third time the tech was there and saw the problem right off.

My Bernina 630,440, and 215 all came with metal bobbins with holes in the sides. I was told never to use any other bobbins for my machines. I think the best thing to do, is to use the bobbins that came with your machine, and if you need more, buy them for your specific machine. I have never used the generic type bobbins sold by chain stores. Sure, they may cost more, but I figure I same money and time. That said, it is possible you could get a warped bobbin or even create a warped one by dropping it on the floor.