For stacking cakes would you just go with the regular American BC? Or is it still "safe" to try the SMBC on it? How fixable is it if it gets dinged while stacking? Is it as stable on a cake as the regular bc? If I have to drive it to the next State can I expect it to stay where I put it?

I've used SMBC on stacked cakes before. So have many, many, other decorators. Of course it does require a bit of skill to fix dings, but it will stay on the cake unless it is melted off....I wouldn't use it for an outdoor wedding in the heat of summer....but yes, you can use SMBC for stacked cakes.

I'm using it on one this coming June.