Collections of MIDI Files are offered "as is" and are subject to change of contents from time to time.
My first Hauptwerk 4 MIDI set, 401 Unregistered MIDI files, is still available.
They are offered for the hobbyist and do not constitute a license to distribute.
Here is a description of how I use the unregistered 401 files.
First, load Hw4 and the organ you want to play.
In your browser, load
As an example, let's look at Ach Gott und Herr, BWV 714. Click on the first one, and a description and possibly a registration comes up in the left frame. Click on the little headphones if you want to hear the MP3. If you can tell from the description you don't want to use it, just click on the next one. When you find the one you want to play, switch to the Hauptwerk window and set a registration that you think will sound well. In Console view mode (VIEW ->Zoom to switch between tiny and too large) You can click with your mouse carefully on manual and pedal keys to hear the sounds with the MP3 still fresh in your ears, or just start playing the MIDI file. RECORDING -> Load MIDI File -> Play MIDI File (F7) - Stop (CTL-SPACE) toggles.
When it suits your taste,
When you encounter 2 registrations in the browser's left window, you can just ignore the 2nd, or just click a general. Any changes you make by hand will be recorded in either format, so be careful not to collide with notes while they're playing.
Some samplers restrict public performance.