What color thread to use on a table rug?

I was teaching a friend how to make a coiled basket and the question of of the day was...
What color thread to use on multi colored fabrics, which can be a tough decision.  If the fabric has lots of wonderful colors then I sometimes use invisible or clear thread, but it is not cotton.  Here is a table rug that has so many bold colors and depending on your color thread choice, you can change the shade of the finished table rug.  Many times I make coasters just to try out different colors on a specific fabric.

I just love this bold floral fabric and made this 16" table rug for great protection. 

This has so many colors it's amazing!
Usually I use the background color for the thread choice, so that it blends in.

 But here I used dark purple for a couple of rows, then I use a dark green, then a lighter kelly green and then a lime green.  It is hard to see them in this picture, but you can see that there are different shades.

Can you see the navy blue section, then the royal blue section and then even lilac?

I wish I could take better pictures.  This is the reverse side of the table rug where I only used dark purple embroidery thread to add to the highlights and I love it!  I will use this side!

See how even the colors look now that only one shade of purple is used.  I plan to make myself a matching basket, but I will use green this time, since the room is painted green or maybe not!

Good luck choosing your thread!
Thanks for visiting!
:)