Anything 9.4 and less is very very reasonable. Even Dracs are reasonable (now) in 9.6 as more 9.8s have surfaced. Except for the early issues of TOD (1-9) even the 9.8s are reasonable.
Werewolf by Night, for some strange reason, have been commanding more than what I believe to be FMV in recent years. I'm howling with laughter over this, as TOD was clearly the best of the "classic monster" series Marvel put out in the bronze age, and outlived the others by an order of magnitude.
In order of preference:
Tomb of Dracula
Werewolf by Night
Frankenstein
Supernatural Thrillers "Mummy"
Some issues that get overlooked when talking Marvel horror are the first issues of Crypt, Chamber, Supernatural Thrillers (before Mummy), Journey into Mystery, and other horror/sci-fi issues that contained original content. The fact these issues pretty quickly went to reprints, with the exception of ST, leaves collectors with the impression the whole run was the same.
There was some good stuff in those early issues...
Jim
I also agree with you that there are more overlooked, (and better) bronze age marvel horror titles, but sterling also said "classic Monster" series. And that is how I would rank these titles in that regard also.