: : : No Gollum came directly in contact with a person that had 9 fingers If there was anyone that didn't speak in metaphores it is Gollum.

: : No where, to my knowledge, in LOTR does it say that Sauron had taken a corporeal (flesh) form. He may have clad himself in a new form. In either case, there's a simple explanation for the missing finger. Sauron could only take a form, flesh or raiment, on that portion of his spirit which was intact. Part of his spirit was missing. It was in the Ring and therefore part of his new form was missing.
: : ~Aelmer

: The form that Sauron took following being wrecked in the Akkalabeth, is the same form that he took, and indeed was the only physical form he could now inhabit, again after his reconstitution in the Third Age.
: This form is described : it was essentially humanoid (this can be safely inferred), it had a black skin and was hot (probably both a physical and moral property) it had a single lidless eye which was rimmed with fire.

: The disembodied "Lidless Eye" was an impression that those beings under Sauron's scrutiny (at a distance) gained. It is not a separate incarnation. Those who were unlucky to have a personal interview with Sauron, as Gollum had, would have seen the whole of his form not merely the eye.

There is another logical (OK I admit sophistrical) argument against the disembodied "Lidless Eye" incarnation. An eye is an eye if it is not in a socket, it is neither lidded or lidless, it's just an eyeball. In order for it to be noted as being lidless (like snakes - which lack eyelids) it, the Eye, must have been in a socket which in turn implies a head, a head a body etc.

QED