There are several formulas from the data collected from graded reviews by critics, enthusiasts, etc. and the "wisdom of the commons," but no "metacritic" data. That would be more appropriate for recent films, as it focuses on recent film almost exclusively. Many of our more recently emerged mouthpieces for noir (no names here but you know where to find them) are extremely cagey about rating films--after all, it wouldn't really do to know that ~35% of the films screened at NC SF over the past sixteen years grade out at 79 or lower (roughly equivalent to 2.5 on your four-point scale)?
Silver/Ward's books have always been highly academic in orientation, almost to a fault. (Which stands to reason, given where many of the participants are/were employed.) The essays about general topics have tended to be much more satisfying than the film reviews in the various editions of the Encyclopedia. You'd probably need to establish some kind of template for discussing the components you mention in a similar sequence and segueing into a grade.
Much of what passes for that in current practice is permitted to be wildly idiosyncratic and willfully piecemeal/inconsistent, as befits the gunslinging mode that's popular amongst the young turks who've just come out of film school. Most of them would rather be left for dead by the side of the road than be systematic.
The book you should track down that takes Keaney's approach to an almost surreal extreme is Wampa12's THE FILM NOIR BIBLE. Many idiosyncratically systematic (is than an oxymoron) ranking lists amongst the often-savage prose!
Scores for the films you reviewed: Nightfall 87, Man in the Attic 80, The Strangler 82. (I do enjoy Victor Buono, but he's too hammy--try imagining THE STRANGLER with Laird Cregar.)