It was a tabloid-circulated image seen round the world: legendary producer and songwriter Phil Spector and his foot-high hair teased to the courtroom ceiling as he sat trial for second degree murder. ''That was the model for this story,'' said Cydney Cornell, the hairstylist who, alongside wig maker Renate Leuschner, helped transform Al Pacino into the title character for David Mamet’s new HBO movie. ''That was something that we had to build up to. It was softer and more realistic at the beginning and it got bigger and bigger and bigger. My research came from headline pictures, and I watched a lot of videotape so I could see what the back [of each hairstyle] looked like.'' As for the curls? ''I permed it myself!'' declared Leuschner, who created the style on a wig block before handing it over to Pacino for fittings.