Well, i used 3mm Hardfoam PVC. Its like Sintra but it needs a higher temperature.
But you should try first with a Paper template before wasting material ;-) If the Jangotemplate wont work, you might get yourself a newspaper and a magic Marker. Press the Paper down on your ankle and mark the lines you think the Plate should look. - Then cutting and unfolding and your got your template (or atleast a raw draft)
i used RAL5010 Enzianblue for the Season2 DW
but Bo's knees fit more with RAL5009 "Azure" and her Cheeks with RAL 5013 "Cobalt"
But i' not sure with the Azure when comparing Bos Pics with the Color palette it could be 3 diffrent colors...
But then Again i recognize that you may not common with the RAL-Palette so i guess "Bleu de France" or "Celestial Blue" could be the one.