Late last night after finishing layering and basting a new work, I wound a couple of bobbins, cleaned and oiled the machine, and most importantly then spent about 1/2 hour making a sample, pics above.  In a sample the best combinations of  thread, needle size, tension and stitch length are all resolved before starting the work on that prisitine, alluring, quilt sandwich; and if nothing else this minimises unpicking.  I used offcuts of the exact batting, backing and front fabrics of the quilt for the sample, and here are the choices I made with its help:

• The whole time I was piecing I had in mind I’d use a neon citrus yellow-green thread for the quilting.  So that’s what I started with, but the  result was disappointing, so I pulled it out altogether, don’t even show it on the sample.   This combination has worked before with these fabrics (see the New Work gallery elsewhere on this website) – but I’m sure it just didn’t translate well to the totally different scale this time (Some examples in my New Work gallery on this website)
• Next option was Gutermann’s Skala light grey.  I’m using it in the bobbin anyway, and always piece with this thread.  Last time I was in the US I bought 4 x 10,000 m cones, in white, dark grey, light grey, cream to add to the dark grey and black I have plenty of.  What I love about this thread is how it blends well with appropriate colours  including prints, in its range.  And for unpicking, you just pull the top thread and it glides out.  A breeze, and yet it is as strong as any other thread for machine piecing, with the added addition of it being so fine it doesn’t cause a ridge on the seamline.  You can tell I’m a fan !  The stitching worked well – see the left side of the pics of the sample, including some topstitching on the orange/purple dots)- and, although the texture would be marvellous, I want ‘more’.
• So my next choice, and one I’m going with, is silver metallic.  There’s no brand name on the very large cone I have.  I then had to decide whether to stitch right at the seamline between the grey and the colour (narrow orange and right end of sample), or to topstitch on those edges(broader bright deep pink strip) as well as out in the plain grey, too –  and I’m going with the topstitch effect.

This is a large work – it will be 2m  x 1m when finished.  The time taken for the sample making, photographing and writing this post about it, perhaps total 2 hours, are a fraction of the piecing plus quilting and finishing – and a worthwhile investment imho that I often make at this point in a new work.  The final check will be several rows into the quilting when I will pin it up and seriously examine whether the look really is what I’m aiming for.     The other two pics in the collage are of interesting points in the quilt which I will re-photograph and post so you can see how different the quilting makes it look.  Note a bit of wrinkling in one of them, which I am sure quilting will camouflage, and there are several other minor spots, too, but in my experience, it will be OK on the day!