A good way to update a one-way mirrored custom field on another board?

Question

Trying to make a TL:DR on the top here.

I have a workflow board that automatically copies and links cards to an editorial calendar board based on a custom field called Publication Date (we use due dates for internal milestones).

On the editorial calendar board, the butler automatically ingests cards, reads the Publication Date and puts it in as the Due date so that the calendar view properly displays deliverables.

This works fine but now I have a problem when someone changes the publication date custom field on the original card in the workflow board. I need an automation that updates the card on the editorial calendar board.

I've tried these two automations

when custom field "Published Date" is set, for each card linked in the attachments, archive the card

when custom field "Published Date" is set, copy the card to the top of list "Content Marketing Publication Dates (Automated)" on board "Editorial Calendar" and link the cards together

but I can't get the order of operations right.

In plain English, this is what I need.

Either:

* When published field is updated on workflow board, update due date on the linked card in editorial calendar board

or

* When published field is updated on workflow board, archive the linked card then create a new card with the updated published date field.

Any ideas short of paying for some ridiculous functionality/plugin?

Thanks.

Hannah Humbert - Simpla Workflows · Answer

It sounds like you need a solution that syncs the cards, rather than copies the cards. Have you looked into Unito?

milynnus · Answer

@gmartin

I have a client from Netherlands that consolidates via copy all the tasks in Doing list of multiple boards into one overview board and it synchronised the due dates to the overall when it is changed on the original boards.

milynnus · Answer

@gmartin

To be honest, it got lost reading your post. I have been find ways to work with due dates on cards and items. You see check it out by going to my profile. Lately there has been many similar question involving dates. 
You have probably discovered that you replicate a due date to another card is not possible with Butler. (I would be glad to be proven wrong). You can use a custom field but you to set it manually. I am aware that it can be done and I wrote a couple of modules which you can call from Butler HTTP request action. That way it is embed with the command.