Preview/Mail printing issue

I am attempting to print PDF's (and save documents as PDF's) as close to full bleed as possible. Right now I am losing approximately 3/4" in margin left, right, top and bottom. Any way to adjust margins in Preview? I do not see the option to create a custom size paper as I've seen suggested as a work-around. On a related note, it appears that an email that is printed from Mac Mail is first converted to a PDF. Is this correct and is there a different method to print email that will not cut off text top and bottom besides pasting it into a Word document?