Hi @sixtyseven
Have you tried using the acf/save_post action to save your information?
http://www.advancedcustomfields.com/resources/acfsave_post/
I think you need to use $_POST if you want your ACF values to work properly.
You say you have a redirect issue? What are you basing that on? Have you looked at the rendered forms markup to see that there’s nothing clashing there like duplicate inputs etc.