Some of the things you prepare on Mac you simply transfer to pc (language settings etc) or vice versa. But I found that the built in Deployment Tool on Windows was good enough for doing some of the preparing.
1. Prepare Omnis
Before you codesign and notarize, you have to test your application carefully. The UI has changed in Omnis 11. Field colors and window positions are not like before.
2. Application Support Folder
This differs between Mac and PC. Omnis on Windows does not have a default firstruninstall folder. I prefer to have the same setup on both platforms. Today there are 2 level of folders in Application Support. One "application folder" and one "version folder". If this is not specified, the default target is /Application Support/Omnis/ which may confuse the customers. So it is advicable to get your customized firstruninstall folder. To get your firstruninstall folder placed in the correct place on PC, you have to edit 2 resources.
/Applications/Contents/Resources/en.lproj/Localizeable.strings
4. Customize Omnis icon to your own icon
Create your icon in Photoshop and save it as 1024x1024 png and add to the Deployment Tool. Than build without notarization. You got an .icns inside the build that you can copy and paste into your runtime library. Note that Sonoma icons in Dock is a bit smaller.
And also note that this icon will maybe not change the desktop icon at once. I had to clear the cached icon by updating the MacOS in order to make the new icon appear in both the Finder and Dock.
5. Localize Yes and No in your library
Omnis relies on that your language is present in the omnislic.df1 file. Just open omnisloc.lbs as any other library if needed add your prefered language. The data is saved within the omisloc.df1
6. Change Info message
Replace Omnis in Show Info
7. Save some MB
Delete database drivers that you do not use.