I know that you can route a workspace in a schedule to use a specific engine, and I know that you can append "tm_tag=fast" to the end of a URL to do the same, but how do you specify a tag when the user runs a workspace in the Run dialog page? I can't expect the user to understand that they have to add "tm_tag=fast" to the URL, they just run the workspace.
Thanks
There is currently no easy way for end users to do this through the FME Server web UI. In FME Server 2017 this capability has been added to the REST API and it looks like there are plans to add it to the web UI in the future (See this post [search for Routing on the page]: https://blog.safe.com/2017/01/2017-fme-server-customer-survey/)
If this is something that you would like to see implemented then it might be a good idea to add it as an Idea and get people to vote on it...