Hello,
You can adjust the maximum uploaded file size in the General Settings section of the Portal Connector Configuration:
To adjust the size of the red dot you could adjust the CSS class ".ruUploadFailure" to meet the desired specifications.
In The Portal Connector v3.0 you are able to modify the template of the File Upload widget, which gives you access to all of the properties and styling defined
here.
Alternatively you could just change the skin on the page using the Form Decorator widget.
Best Regards,
Clinton