Enable a CTA triggered by a Rule to have a due date based on a field value instead of rule date

Related products: CS Rules & Permissions

I have a rule that creates a CTA whenever we have a new customer with an opt-out clause in their contract. I'd like to be able to set the CTA due date to equal the Opt-Out-Deadline Date. Currently my only option is Rule Date + __ Days. 
FYI - I have a similar request for more flexibility on the CTA due date.  My customer wants to be able to create lifecycle CTAs for new Enterprise customers with the due date to be last day of the year.  In their process, it's the responsibility of the Enterprise CSM to meet with the customer and schedule all the touch points to align with the customers' fiscal calendar, events, etc... Thanks.