The rules are based on single-figure removal of casualties, though it's easy enough to use some form of counter to keep track of hits on a multi-base. Also looks good if you substitute a base of 3-4 15mm figures in place of a single 28mm.
The official unit sizes are as follows, although there are optional rules for under-strength and half sized units. In each case one figure should be identifiable as the Leader:
Regular Infantry: 12 figures
Irregular Infantry:12 (shooting types)
Tribal Infantry: 16 (charging types)
Assorted Mounted types: 8
Artillery: 1 gun plus 4 crew
