I reckon there is some hidden code in SQL that recognises what database it is connected to, as have "issues" with Discover on our training laptops immediately after replacing out of date SIMS training datasets. I have got it to run I SIMS but have difficulties running the Transfer Utility (especially the larger GA database).
The idea is that you have 2 versions of all the Config files in Discover Services and "Discover.Designer.Desktop.exe.local.config" in the C:\ProgramData\Discover folder - 1 each for GA & WE, where they include SIMS & Discover variables. You stop the Discover services, overwrite said files with the appropriate copies for the database you are accessing, then restart the services. I have also found that it works better if the laptop is set as a hosted SQL server.