I'm making a mountain cake for my nephew's 40h birthday.  It will be covered in buttercream and I want to make him and his family as skiing and skateboarding figurines.  I've never made modelling chocolate figurines before but figured that they would better withstand the buttercream than fondant.  Can anyone let me know how far in advance I can make the modelling chocolate figurines an show to store them? Many thanks

You can make them now.  If you want them to dry completely, store them loosely covered. Make sure they stay away from heat and out of direct sunlight.  If you want them to remain somewhat pliable, store them in an airtight container and again, away from heat and sunlight.  If you don't want the buttercream to affect them, put them on the cake as the last thing.

usually buttercream does not affect modelling choco -- only heat usually

Many thanks for you quick and informative answers!

Modeling chocolate figures stay nice indefinitely if kept at normal room temperature or lower.  I usually just set small pieces in a shoe box, lightly covered. I have a few pieces that I've had for over three years and they've changed very little.  No, buttercream will not damage the modeling chocolate.

Since you have never previously used it, start early and give yourself time to get familiar with it's characteristics, because it is very different than fondant or gum paste.  Mainly, it will melt in your hands.  If it starts to get too soft and oily, just walk away for a few minutes and let it cool off and let the oil reabsorb.  That being said, it is by far, my favorite medium with which to work and it sure tastes a lot better!  Good luck!

Thank you Sandra!

You are very welcome!  If you have questions, give me a shout.  I've used  A LOT of modeling chocolate.