So update:
The beans from 2010 are showing tap roots.
The beans from 1970 have opened or split, but no tap root yet.
And for all the other variously aged beans, at least 1 from each strain is showing a taproot 
Tonight is a full moon, which I knew aids in germination, so I’m glad I started my soaks 2 days ago. The timing is perfect. I have a great feeling these 70s beans will sprout within a day or so 
I let them dry out from the soak because it was a 24 hour one and I didn’t want them to drown or get to soft. So they were centered on a unbleached coffee filter, and placed in a small sterile ziplock. I let them sit there dry for a few hours before I came back and sprayed some warm water inside. Then I sealed it back up and placed it over my PS4 to keep them warm.
Im going to try and find some GA3 online for any future experiments, but so far my method seems to have been a success !