We're actually not using it much anymore. After hearing how other user's handle things at Leap we decided to move most of our info to the Program and essentially use it to house the 'master proj' data. We are still creating a 'master', but what we were using as sub-projects are now just projects under the same Program as the master.
And I up-voted your Idea! I also added one in Other for Best Practice location in the Community - please up-vote!! :) In keeping with that, below are my calcs when using the Issue conversion for 'sub-projects'. This particular calculation provides a link to the Master Project on the sub-projects you create (I thought it would be helpful for users to always have a way to get back to the master). I came across the URL on the help site here,
https://support.workfront.com/hc/en-us/articles/217518067-View-External-URL-Using-Custom-Data-Field, and then just updated it to pull Project not Task overview info. Lastly, the Help site mentions copying a Proj Custom Form and saving as Issue Custom Form in order to pull stuff through (you have to update calcs though), we ran into issues with this where we had a changed a name on the Proj Custom Form (and deleted others that had previously been on the form when it was copied) which then broke the Issue Custom Form, just an fyi. Thankfully we haven't fully launched yet so were able to fix.
Carrying through calculated field from master project to sub project via issue conversion - trick is to name all of the fields the same as the original one but change the calculations
1. Put source calculated field on MASTER.
2. On ISSUE, from the library, use the calculated field from step 1 but change calc to Project.{source calc field}.
3. Attach form to the issue and convert to project.
3. On SUB PROJECT custom form added at conversion or on the template , use library calculated field again but change calc to IF(ISBLANK {source calc field} ,"", {source calc field} )
Example: MASTER PROJECT CUSTOM FORM- Label: Master Project URL Calc: CONCAT("https:// YOURDOMAIN .my.workfront.com","/","project/view?ID=",ID,"&activeTab=tabs-project-details-forms")
ISSUE CUSTOM FORM- Label: Master Project URL Calc: Project.Master Project URL
SUB PROJECT CUSTOM FORM- Label: Master Project URL Calc: IF(ISBLANK(Master Project URL),"",Master Project URL)
When I'm not pulling a system field like the URL, I enter "Please update this on the X Custom Form" so that users know where to go to fix it since they can't edit the calc field on the lower object.
Hope this makes sense and helps some - thanks for reaching out!
Ondina