ZBrushCentral

How to subtract one subtool from another

Hi, I am new to the zbrush world, using R2, and I keep encountering one big hurtle. That is I want to be able to subtract a sculpted object from another. For example if I were to sculpt a head as one subtool and a helmet as another, then to get a perfect fit I would want to subtract the shape of the head from the inside of the helmet to create an exact alignment. The booleans seem to get me close but it comes out soft and I loose all my hard edges. When I use the ProjectAll I can only get it to successfully shrink-wrap over the positive shapes, I can’t seem to get it to subtract. This might be me not understanding booleans correctly or I might be asking it to do something it can’t.

Also I think I can go through the Meshinsert Dot tool by importing my sculpted object but this is rather difficult to get it to the exact right size and alignment. Any help would be greatly appreciated. I apologize if there is an obvious solution, please point me in the right direction. If someone has a link to a video tutorial that would be amazing. And please feel free to dumb it down, I am still not up to speed on all of the terminology. Thanks