I have not stenciled but I have done buttercream transfers onto IMBC and SMBC using crusting buttercream for the transfer. Works great

AHow on earth do you stencil on mbc quick enough that it doesn't mess up the icing when you pull it off? Obviously you do it on a very thoroughly chilled cake, but the top layer starts to get soft quick. I'm not seeing this in my head.

I was planning on stenciling onto American Buttercream (chilled via fridge so firm). Would a shortening based crusting BC be the best bet to act as the stenciled design here? Or should I use the same American Buttercream on the stencil.

Any thoughts? Thank you!