Hey I like those parameters. I would say the condition of Medusa's head is more important than Perseus's head but ones with his facial features showing seems to be the most rare. What interests you in this coin? The blood? The rarity? or difficulty in finding a pristine specimen? I love the myth of Perseus.
Apropos of this thread, I feel compelled to show again a picture from my trip to Italy last Fall. This was photographed in Florence, and is my favorite bronze sculpture of my trip. Perseus with the head of Medusa by Benvenuto Cellini, 1545: The decapitation resulted in the birth of the winged horse Pegasus from the neck of Medusa.
Pontos Amisos Mithradates VI 109-89 BC AE 28 Athena Perseus Medusa Head Body Fortunately, my Medusa body seems there, neck looks like it is spurting blood... but it looks like SHE got Perseus' head too.
Since this came up, I'll share another favorite of mine. Even as these beheaded Medusa coins that Mithridates issued were circulating in his kingdom, his great enemy the Roman Republic had a moneyer who struck denarii with the bust of Medusa on the obverse and the hero Bellerophon riding Pegasus on the reverse. Bring it on, Perseus! ROMAN REPUBLIC C. Cossutius C.f. Sabula AR Denarius 3.86g, 18.6mm Rome mint, 72 BC Babelon Cossutia 1; Sydenham 790; Crawford 395/1. O: SABVLA, Head of Medusa left. R: Bellerophon on Pegasus right, brandishing spear in right hand; below, L COSSVTI C F; behind, IIII.