On the basis that "many eyes make all bugs shallow," here are my thoughts on Chris's Giallo Score project, for you to comment on / add to / critique.
Possible criteria and scores, and comments on and modifications to existing scores:
Spanish director - 7 points
Many gialli were Italian-Spanish co-productions; some also saw the Spanish side of the production predominate. This would, I think, allow for films such as the Paul Naschy vehicles A Dragonfly for Each Corpse, The Blue Eyes of the Broken Doll and Seven Murders for Scotland Yard to be recognised as closer to the giallo than otherwise comparable Anglophone productions such as Don't Look Now and Dressed to Kill.
Black gloves - 10 points
Reduce this, in conjunction with:
Distinctive costume - 10 points
The killer wears at least two out of three of a (dark) raincoat and fedora, and a (light or dark) mask.
Golden age (1970-1975) - 5 points
A slight change in the year span, to end with Profondo Rosso
Silver age(s) (1963-1969 or 1977-1982)
The film was released in either of these periods, the former beginning with The Girl Who Knew Too Much and the latter ending with Tenebre and The New York Ripper.
Accidental / purposeful death
Where would Cat o' Nine Tails fit here? Is it a one, a ten, or an eleven? Or Profondo rosso? How far is self-defence causing death purposeful?
Urban location - 3 points
The giallo is essentially an urban genre. Adding this would, I think, allow for further distinctions between Italian urban (8 points); non-Italian urban (Seven Yellow Silk Shawls, 3 points); Italian rural (Don't Torture a Duckling, House with the Windows that Laughed; 5 points) and non-Italian, rural (the odd slasher-ised 80s entry like Deodato's Body Count; 0 points) to be drawn.
Contemporary setting - 3 points
Some Italian horror films set in the past, such as Freda's Hichcock diptych and Margheriti's Seven Deaths in the Cat's Eye, could be considered gialli as they avoid the supernatural. This might allow the contemporary counterparts such as The Night Evelyn Came out of the Grave and The Red Queen Kills Seven Times to be recognised more.
Tits, tits and ass, full frontal as 1, 2, 3 points? 1 point for a sex scene?
Morricone / Nicolai - 2 points
What happens if a film is scored by Morricone and conducted and/or arranged by Nicolai? Might this be worth four points?
One point for each of Stelvio Cipriani, Goblin, Gianni Ferrio and/or Piero Umiliani?
Animal or Death in the title - 1 point
Also one point for a number - Six Women for the Killer, Nine Guests for a Crime, Cat o' Nine Tails etc.
More than one killer or accomplice - 1 point
Perhaps a bonus points for three plus killers and accomplices, as in the 1972 Delirium and A Bay of Blood.
The Fall - 1 point
At some point someone dies by falling from a considerable height.
J&B - 1 point
J&B whisky is displayed prominently
Punt e mes - 1 point
Punt e mes is displayed prominently
The priest or fake priest - 1 point
There is a priest and/or fake priest, who may be a red herring or a killer
Dolls or dummies - 1 point
At some point dolls or dummies are prominently featured
Glamour and models - 1 point
One of the characters is a model and / or a studio or fashion house is featured
Gay / Lesbian characters - 1 point
There is at least one character who is gay or lesbian.
West German co-production - 1 point
For Argento's giallo-krimis and others circa 1970-72
Increase from 10 to 15 or 20 points, to allow for more recognition of those films that may not check all the boxes, but are nevertheless definitive, such as Profondo rosso.
Increase from 5 to 10 points, to help ensure Blood and Black Lace score higher than the late-60s Lenzi films, even if Bava's influence was perhaps indirect, filtered through Argento.