There is a web site dedicated to making pinhole cameras, don't remember where at the moment. I believe your aperture and f/stop is wrong for focal length, should be much smaller. I'll find the site and give you the url.
link to pinhole calculator:
To find out how much to wind film between shots, use some spent film and measure how much is spooled for every revolution of the winder and extrapolate.
BTW, welcome to the clan.