Ola David,
All the times I needed to break glasses, I used Blaster, because my films needed to appear a explosion, Rodeo don't have a "bomb" energy, like Blaster or Mr Nitro.
To model, I did Pre-cuts on EIM, worked fine with knive tools, I used once FormZ to do a broked wall glass, worked fine.
Don't forget to create your models in a big scale, otherwise, Blaster or Rodeo will have prbs with small pieces of the glass and they will give you errors.
Hope this help
Thanks
Tom