Machine Quilting - The Travails of an Inexperienced Quilter

I was quite pleased with this Disappearing Nine Patch patchwork top for a small quilt and I was pleased at how I was improving at getting the corner seams to match.  That was until I decided that I would have a go at machine quilting.

I prepared well.  I read reams of online written material and looked at countless online videos.  I knew it all. I considered the variables - the sewing machine, thread , needle, tensions, foot, pressures and stitch length in relation to the layered fabric I wanted to stitch.  I tried them out on a sample pieces.  All seemed well.  But I was deluding myself.  Once I got onto the real thing this is what happened.

Invisible thread - kept snapping.
The ditch in the stitch foot raced the bottom layer through at twice the speed of the top layer.
My diagonal quilting looked ghastly - the thread was all the wrong colour for stitching on top of such a variey of coloured fabrics.  I unpicked the lot.  That's when I took the above photo.

By this time I was using the Walking Foot but the tension would look OK for a moment then the tension would go haywire.  Stitch in the Ditch became Stitch somewhere in the Vicinity of the Ditch,.

Everything I did became a case of Exterminate !  Exterminate ! Unpick !  Unpick !

Last hope - Yesterday when buying some extra reels of cotton at a haberdashery the assistant said that she always used a Metallic needle for quilting so I tried that and now everything is just purring along beautifully.  I had already tried some-one else's favourite, a Denim needle and it wasn't too bad, but the Metallic one is just perfect.  It beggars belief, though.  Everything I've tried was a size 80 yet the needle designed for doing machine embroidery with metallic threads is the one that works best for me. Any problems now relate to my ability to feed the fabric along the stitching line into the walking foot.

At the moment it's quilted with lines 12 1/2" apart.  Next step I suppose will be to stitch in the ditch half way between these lines.  That's going to look awfully boring on the back but I don't want to tackle any stitching which involves massive amounts of rotating the quilt to stitch around smaller squares.

My machine is a few years old.  A Janome Memorycraft 3500.  All this time and we have never been on such intimate terms as we have been the last few days !