They had no set spacing or even justification.

That brings back memories of a school project whereby I typed up quite a bit of text fully justified - using my mother's manual Remington typewriter from the 1930's...IIRC each line was typed out once to work out where the extra spaces would be least noticeable and then typed again justified. Because of the tedium and probably frequency of mistakes, I think I did it a small amount at a time, cut the section out and glued it to a bigger sheet of paper...