It's trial and error in finding the 'sweet spot' for the foot height. You don't want it high so that the fabric 'bounces' but you don't want it too low that you can't move your sandwich or go over seams.

Also, the another 'sweet spot' is the speed of your machine. I listen to my machine sound when the stitching is moving the way I want it to go with no skipped stitches, then try to use that speed while at the same time moving my sandwich at a speed that is in union with the machine stitching.

It sounds difficult, but it really isn't. Just take your time and work on a practice piece until you get comfortable. Also, for another for thread breakage - I always put in a new needle when I switch from piecing to quilting.

Just another suggestion, did you try a different needle? Certain needles on mine do not like to sew sideways, especially to the left. Having trouble sewing backwards is puzzling.

OK, this will make you laugh. My quilting machine never gives me trouble sewing backwards, until today, the day after I posted a suggestion to you. When the thread broke on a backwards run I just laughed. Karma!

You should have knocked on wood before you posted Haha. My MIL gave me some organ needles to try. Says her Janome likes them. Has your machine come around?

Yes, it just did it one time to show me it could!