Maybe the 914 site on dgi.net is no longer. They had a table of advance curves, mechanical and vacuum.
I have a 73 2.0 but the dizzy has an unknown vac can and one of the springs had been replaced with a stiffer one as far as I can tell. Can't find the springs anywhere, but I think I can score a correct vac can.
Easy thing to do is steal my 72 1.7 dizzy and use that, but I am curious how far off the advance curves between the two.