Sakas copied Indo-Greek coinage extensively.  Their coinage weighed between 2.0 gms to 2.5 gms. While adopting many Greek features, they also employed their own attributes in the coinage.  Though there are distinct types of coins issued by the Sakas, the main type was continued by many dynasties. Nahapana's coinage is the first in the same series, which resembled Greek style hemidrachms.  The well executed coin portraits of Nahapana shows him in youth, middle age, and old age.  It is really remarkable to see metamorphosis on his coinage. The reverse featured thunderbolt and an arrow.

Chastana's coins resembled that of Nahapana's  which in turn reminds of Apollodotus's coinage.  These hemidrachms are abundantly found throughout Western India and carried the symbol Chaitya as copied from early Andhra coins. The long monotonous issue of drachmas of the ruler Jivadaman and his successors dates in Saka era which helped in timing the historical events till the Gupta conquest (395 AD).  Though Chastana dynasty ended earlier, the portrait coinage had a further lease of life through Guptas, Bhattarakas, Mukharis and even the invading Huns!.

All in all, what can be highlighted is  - all the later Chastana coins carried three hilled peak on the reverse, but the obverse portraits had the differences in the eyes, noses, hair and hats of rulers.
Viradaman had the Greek nose, straight from the forehead without bridge, his brother, Damajadasri-III had a hooked nose.  The squarish cap distinguished the ruler Rudrasimha-II whereas his brother Yasodaman-II had a round cap. Thus all the Satraps could be easily identified through these minor variations in the hair style, eyes, nose, cap etc.,

But anyway, the best way the coins could be identified is through the Brahmi legend around the Chaitya symbol, those coins carried on the reverse.  A typical inscription "Rajna Mahaksatrapasa Svami Rudradamaputrasa Rajna Mahasatrapasa Swami Rudrasenasa." identifies the father Rudradaman and the current ruler Rudrasena.