With the Fourth of July falling in the middle of the week, studios and theaters are figuring on a six-day holiday. Good thing, too, since weather forecasts for the Eastern part of the nation for the Fourth itself call for storms, heat, and humidity. Tracking surveys suggest that The Amazing Spider-Man , with Andrew Garfield replacing Toby Maguire in the title role, will likely produce some amazing business -- around $110-120 million over the six days from 4,315 theaters, three-quarters of which will be screening it in 3D or IMAX. That figure may be conservative. The original Spider-Man earned $114.8 million in its opening weekend in 2002. Spider-Man 2 opened on a Wednesday in 2004 and collected $152.5 million over five days. The third Spider-Man flick in 2007 had a record-setting three-day debut of $151 million. The Sony/Columbia movie is expected to be just about the only game in town until the arrival of Warner Bros.' The Dark Knight Rises on July 20. Paramount is counter-programming it beginning on Thursday with Katy Perry Part of Me aimed at young girls, and Universal is launching the Oliver Stone thriller Savages on Friday. Each film is expected to earn less than $15 million.