300mm or 360mm sounds likely. The lens is somewhat wide for portraiture, based on the shape of the face. The lighting is pretty obvious from looking in the eyes, two huge soft lights very close to the face, serving as both a wash of very even, shadowless light and eyelights (the "window to the soul").
Save money and shoot it on 4x5! You'll need 1/4 the light and film will be cheaper, too. (Just saying this since I don't have an 8x10.)
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