Hello @specter33,
I believe what you want to achieve could be done using jQuery but it’s a fairly complex development topic. I’m going to leave this thread open for a bit to see if anyone is able to chime in to help you out.
This guide on how to set the value of an input text field using jQuery might point you in the right direction:
https://www.geeksforgeeks.org/jquery-set-the-value-of-an-input-text-field/
I can also recommend the WooCommerce Developer Resources Portal for resources on developing for WooCommerce and the Using jQuery guide.
You can also visit the WooCommerce Facebook Community group or the #developers
channel of the WooCommerce Community Slack. We’re lucky to have a great community of open-source developers for WooCommerce, and many of our developers hang out there, as well.
Cheers.