When you are working on a patch in MainStage, it's important to save often.
When working inside Sunday Keys we recommend making duplicates of patches as you look to save your own presets. Once you've dialed in a sound you'd like to save using the on-screen controls, save the concert (⌘S) and/or export the patch (⌘E) before switching to a different patch. From there MainStage will recall those on-screen settings when you next use the patch. It's also a great best practice to export your patch once it's complete (into a folder of your choice inside your MainStage folder) so you can get to it easily when you want it again. This way you won't need to search inside a bunch of different concerts to find one patch you created months ago.