You install each new test build on top of the old test build. That updates it and retains all settings, addons and Library.

As far as finding the right database you'll have to try each install and check which one is the right one.

Please, best method for installation of new test builds without losing settings/playlists/scripts etc. from previous version? I'm installing the updates in C:MediaMonkey Portable, and now the folders/previous versions are all mixed together, big mess. - Do you create a new folder in C: for each update?
- each installation, I have to again set up scripts, playlists, all settings from scratch; any way to do this automatically?
- this 8.1 pc has 2 standard installations MMW4; then added Beta; then Portable Beta several installs; I've copied DB file but am confused as to which DB file contains hours of tag cleanup, duplicate deletions, etc. So I"d rather not do a clean install and lose all that work. one installation has > 100GB of tracks, mostly duplicates of a 38 GB library. How can i find the DB and settings for that 38 GB library?
thanks!