It likely didn't help that many of the pages were typed carbon copies or hand-written. For the former I had to put another piece of paper behind the page to prevent the next page from bleeding through.
That said, I managed to get the job done, though it took a couple of weeks. Next is to capture the metadata (author, date written, ...). There were a lot of one page letters in the documents I copied.
Would love to try out another tool that could read from the ScanTailor project file to get the page segmentation or even the warping I did manually to improve on the result.
If you have the option go for scanning.
Scans still benefit from cleanup, such as rotation and adjusting the levels (making everything near white perfectly white) and possibly manual cleanup (removal of specks of dust or the odd hair that was on the scanner).
They still warp, but less than laying flat on the table and it's quicker if you do all the even pages, then all the odd pages. Actually the hardest part is making the camera stable so it doesn't move when you press the button.
Lots of info on different hardware setups and scanning software here that can batch translate into pdf and different formats.