It would help to know the current style and what you are after.
It may help with guesses.

From your description, one option would be to use BiaB to find the desired style. It is faster for this.

Save As an sgu file format and open in BiaB .. tinker until you find the drums you like, then remember what style it was and go back to the RB project.
Whatever gets the job done quickest.

There is also an Edit-Fill Track with MIDI Drum .. if that is more what you are looking for. It's basic, but quick and often simple. Not 'Real' players though.

I do not work here, but the benefits are still awesome
Make your sound your own!