Hi,
Technical details for the different types of Traffic Shaping supported in IOS can be found f.e. at "Regulating Packet Flow Roadmap" and subsequent chapters.
http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a008044308f.html
To answer your questions:
Depending on which type of traffic shaping (FRTS, generic TS, class-based TS, distributed TS) you are using the queue size is configurable or not. Follow the above link to pick the type you are interested in and you will find the details.
Bc is "Burst committed", which you might also call normal burst size. Once again it depends a bit on the type of shaping or policing what the exact meaning and the units are.
Hope this helps! Please rate all posts.
Regards, Martin