Hi Lars,
I don't currently have a way for you to set defaults but it is something I'm pondering for the future.
Currently there is a global way to set the max range of the slider question, you can add this in user.config:
<add key="FormWizardPro:SliderMaxRangeLimit" value="10" />
10 is the default value but you could change it. However this setting is global to all instances of Form Wizard. At some point I might make it an instance level setting, that would be fairly easy to do.
Best,
Joe