We have submitted your request as a feature request to our Module Builder team. Here is the link
where you can give us more details about the way you want to define the default value of the field.
Please feel free to contact us again if you need further assistance.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items