re: Have you used Mexican paste?

I’ve used it. Pretty easy to work with. I have not made a figure. I used it to make a picture frame and small decorative pieces. Dries very hard. I’ve tried different recipes, but the one I like the best is from Global Sugar Arts. It also freezes very well. It’s a quick YouTube video. Posted below.

You could always make a small practice figure and see what you think.
Hope this helps.