A family of Microsoft relational database management systems designed for ease of use.
BaptM,
Yes. Since bar styles are part of a view and a view is resident in the Global, all you need to do is to create a custom view, or views, each with your desired bar styles. Note, if your desired default view is based on an exiting view, (e.g. Gantt Chart), I recommend you make of copy of the existing view instead of directly modifying the existing view directly, in case you want to revert back to the default view. Then go to File > Options > General group and set the "Default view" to your customized view.
Once your new custom view is created, go to File > Organizer and transfer your custom view and the associated custom view table, (and filter and group if applicable), to your Global. Exit Project to save the Global.
The next time you start Project it will open to your custom view as the default.
Hope this helps.
John