I came across this solution when I had about a ton of posts (200+) with values in various PDFs. I didn't want to have to spend time filling out the same values over and over again.
This case is pretty straight forward; I have one repeater field field_123a56b7cb890 that has a text fields inside it (field_588a24c3cb782). I haven't tried any other types like post objects or radio buttons, but I'm sure it can be done.
Step 1. Hook into acf/load_value on your repeater field. You can use type/key/name as desired here.