Within the workflow, we used a unity script to access the XML from the disk group and then invoke doc comp. Because it's running locally, it's much faster. It's also disconnected from the process that initiates the composition, which fixed the timeout.
The initiating process just stores the XML document in OnBase, which is provides a return of success quickly. The docs are inserted into workflow by default. A workflow timer processes them and composes the desired documents via script. The composed docs can then go through a workflow to inform the initiating system that they were created by making a web call, if desired. The XML docs can be retained or purged.
