I have a few question about semi-naked cakes, has anyone used Swiss BC on them.  Does it hold up well, especially in heat, venue is AC.

I have used Swiss BC on my naked and semi-naked cakes. It has worked very well for me. Can't say much about the heat though. When it's been "hot" around here I've used a bit of shortening in place of some of the butter. I'm not sure I needed to do so, but it made me feel more confident.