So sorry for all your FMQ woes - I can definitely relate to your problems (your writing is fabulous!). I have given it up for now but I do admire your persistence and determination. Straight line quilting is all I have done and probably will continue for now.
My suggestion would be to find a LQS or someplace that offers a variety of quilting lessons. If you live not too far from such a place, that might be your best bet. One where you can bring your own machine and get some expert advise might be useful for you too.
Good luck!