What kind of applique stitch were you planning to do? If it's machine satin stitch, I think I would do it in gold. This is about the only place I would use my rayon thread. It doesn't take as much wear as other threads but I have one that is in a medium gold (not bright gold) about the colour of your background. You might be able to find something similar. If you want to go to the extra trouble of changing the thread colours, it would look spectacular. Your applique looks awesome!