"In my partition recovery effort to my amazement photorec has saved a number of pdf files over 1GB"
photorec is kinda dumb with files over 800 mbs
those you recovered could be mpg or avi files, or could be just garbage
if you had those files, edit pdf you need a pdf editor, the structure of a pdf is complex viewing it with a hex editor
about a hex editor capable of handling files this big
there is a windows hex editor, very popular, can't remember the name now, it almost could handle a 22mb file i tried to load, anything over 500 mbs is a waste of time i think