For different sized cushions, like Revolution and Blooming Marvellous, I use www.thefeathercompany.com . I always get a cushion pad bigger than the canvas, this is because I like cushions to be really plum. So for example, for the 50 x 50cm maps I get a 60 x 60cm cushion pad.
I stock a variety of linen and velvet backing fabrics, which are cut to size for the different size canvases.
For You Make Me Daisy I chose the Grannie Smith Green velvet.